Engine Control Module: Service and Repair

PCM Mounting:

PCM With Knock Sensor Module:

PCM Replacement
Service of the PCM should normally consist of either replacement of the PCM or EEPROM programming. If the diagnostic procedures call for the PCM to be replaced, PCM should be checked first to see if it is the correct part. If it is, remove the faulty PCM and install the new service PCM. The Knock Sensor (KS) module from the old PCM must be transferred to the new PCM.

Programming Note
THE SERVICE PCM EEPROM WILL NOT BE PROGRAMMED. Diagnostic Trouble Codes (DTCs) P0601 and P0602 indicates the EEPROM is not programmed or has malfunctioned.

Important:
^ When replacing the production PCM with a service PCM (controller), it is important to transfer the broadcast code and production PCM number to the service PCM label. Do not record on PCM cover. This will allow positive identification of PCM parts throughout the service life of the vehicle.
^ To prevent internal PCM damage, the ignition must be OFF when disconnecting or reconnecting power to PCM (for example, battery cable, PCM pigtail, PCM fuse, jumper cables, etc.).

Removal Procedure

Notice:
^ To prevent possible electrostatic discharge damage to the PCM, do not touch the connector pins or soldered components on the circuit board.
^ The ignition should always be OFF when installing or removing the PCM connectors.

1. Remove the PCM from the mounting hardware.
2. Disconnect the Harness connectors from the PCM.
3. Remove the PCM from the engine compartment.
4. Remove the KS Module access cover.
5. Remove the KS Module.

Installation Procedure
1. Install the KS Module into the PCM.
2. Install the KS Module access cover.
3. Connect the Harness Connectors to the PCM.
4. Install the PCM into the vehicle.
5. If a new PCM is being installed, program the EEPROM.

EEPROM Programming
1. Setup - Ensure that the following conditions have been met:
^ The battery is fully charged.
^ The ignition is ON.
^ The Vehicle Interface Module cable connection at the Data Link Connector (DLC) is secure.

2. Program the PCM using the latest software matching the vehicle. Refer to GM Techline terminal/equipment users instructions.

3. If the PCM fails to program, proceed as follows:
^ Ensure that all PCM connections are OK.
^ Check the GM Techline terminal/equipment for the latest software version.
^ Attempt to program the PCM. If the PCM still cannot be programmed properly, replace the PCM. The replacement PCM must be programmed.

Functional Check
1. Perform on board Diagnostic System Check.
2. Start engine and run for one minute.
3. Scan for DTCs using the scan tool.
4. If DTC P0325 sets, the KS module is not fully seated, is missing, or is faulty.