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Home >> Chevrolet >> 1998 >> Corvette V8-5.7L VIN G >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Relays and Modules - Computers and Control Systems >> Engine Control Module >> Service and Repair >> PCM/TAC Module Replacement/Programming

PCM/TAC Module Replacement/Programming

IMPORTANT: Do not substitute a PCM from another vehicle for diagnosis. The PCM will not recognize the Vehicle Theft Deterrent password from the BCM. The PCM disables the fuel, and the PCM stores DTC P1631 into history.

IMPORTANT: The following must be performed anytime the PCM loses power or is reprogrammed:
1. Programming of the EEPROM
2. The Idle Learn Procedure
3. The CKP System Variation Learn Procedure
4. The Functional Check

The following must be performed anytime the PCM or the battery is disconnected:
1. The Idle Learn Procedure
2. The Functional Check

Removal Procedure

IMPORTANT: Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM module connector gaskets when diagnosing/replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the PCM.

NOTICE: Do not touch the connector pins or soldered components on the circuit board in order to prevent possible electrostatic discharge (ESD) damage to the PCM.

IMPORTANT: The ignition should always be OFF when installing or removing the PCM/TAC module connectors.

1. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
2. Remove the right front tire and wheel assembly. Refer to Wheel Removal.

Description:




3. Remove the wheelhouse filler panel. Refer to Wheelhouse Filler Replacement.




4. Remove the fasteners retaining the Throttle Actuator Control (TAC) module to the PCM mounting bracket.
5. Remove the electrical connectors from the TAC module.
6. Remove the TAC module from the vehicle.


IMPORTANT: The remaining steps are for the PCM replacement.


Description:




7. Disconnect the PCM electrical harness connectors.
8. Loosen but do not remove the PCM rear retaining fastener. Use the rear retaining fastener as an anchor for the outer bracket.
9. Remove the front retaining fastener from the PCM.
10. Reposition the PCM outer bracket.
11. Remove the PCM from the bracket and the vehicle.


Description:




Installation Procedure
1. Install the PCM to the PCM rear bracket.
2. Position the PCM front bracket.

NOTICE: Refer to Fastener Notice in Service Precautions.

3. Install the PCM front retaining fastener.

Tighten
Tighten the PCM retaining fasteners to 2.2 Nm (17 lb. in.).

Description:




4. Connect the electrical connectors to the PCM.




5. Connect the electrical connectors to the TAC module.
6. Align the hole in the rear mounting tab of the TAC module to the corresponding hole in the PCM mounting bracket. Position the TAC module below the rear mounting tab for greater clearance in order to install the rear retaining fastener.
7. Install the TAC module rear retaining fastener.
8. Align the front mounting holes of the TAC module.

NOTICE: Refer to Fastener Notice in Service Precautions.

9. Install the TAC module front retaining fasteners.

Tighten
Tighten the TAC module retaining fasteners to 1.9 Nm (17 lb in).

10. Install the wheelhouse filler panel. Refer to Wheelhouse Filler Replacement.
11. Install the right front tire and wheel assembly. Refer to Wheel Removal.
12. Lower the vehicle.
13. Program the EEPROM if a new PCM is being installed.




EEPROM Programming

Setup
1. Ensure that the following conditions have been met:
^ The battery is fully charged.
^ The scan tool cable connection at the DLC is secure.
2. Turn OFF the ignition.
3. Remove the passenger side (right side of vehicle) floor access panel.
4. Remove the splice pack/star connector shorting bars from both splice pack/star connectors (2 and 3). It may be necessary to remove the splice pack/star connectors (2 and 3) from the mounting positions.
5. Install the Star Connector cable #1 from the Serial Data Link Tester J 42236 to the 12 pin splice pack connector (3). This is the connector with 8 or 9 wires.
6. Install the Star Connector cable #2 from the Serial Data Link Tester J 42236 to the 12 pin splice pack (2). This is the connector with 4 wires.
7. Select Star Connector #1 on the Serial Data Link Tester J 42236 toggle switch.
8. Select position B on the Serial Data Link Tester J 42236.
9. Turn ON the ignition leaving the engine OFF.

IMPORTANT: Perform the theft deterrent password learn procedure if a new PCM is installed. Refer to DTC P1631 Theft Deterrent Password Incorrect.

10. Program the PCM using the latest software matching the vehicle. Refer to the Techline terminal/equipment users instructions.
11. If the PCM fails to program, proceed as follows:
^ Ensure that all PCM connections are OK.
^ Ensure that all connections at the Data Bus Diagnostic Switch Box and splice packs are OK.
^ Ensure the proper settings on the Data Bus Diagnostic Switch Box are OK
^ Check the Techline terminal/equipment for the latest software version.
^ Attempt to program the PCM. Replace the PCM if the PCM still cannot be programmed properly.
^ Program the replacement PCM.
12. Perform the theft deterrent password learn procedure if a new PCM is installed. Refer to DTC P1631 Theft Deterrent Password Incorrect.
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