GM Service Manual Online
For 1990-2009 cars only

Service of the PCM should normally consist of either replacement of the PCM or electrically erasable programmable read only memory (EEPROM) programming. If the diagnostic procedures call for PCM Replacement, check the PCM first to see if the replacement is the correct part. If the PCM is faulty, remove it and install the new service PCM.

The new service PCM will not be programmed. You must program the new PCM. DTC P0602 indicates the EEPROM is not programmed or has malfunctioned.

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.

Notice: Turn the ignition OFF when installing or removing the PCM connectors and disconnecting or reconnecting the power to the PCM (battery cable, PCM pigtail, PCM fuse, jumper cables, etc.) in order to prevent internal PCM damage.

Important: When replacing the production PCM with a service PCM (controller), you must transfer the broadcast code and production PCM number to the service PCM label. Do not record this information on the PCM cover. This will allow positive identification of PCM parts throughout the service life of the vehicle.

Removal Procedure

    Important: It is necessary to record the remaining engine oil life. If the replacement module is not programed with the remaining engine oil life, the engine oil life will default to 100%. If the replacement module is not programmed with the remaining engine oil life, the engine oil will need to be changed at 5000 km (3,000 mi) from the last engine oil change.

  1. Using a scan tool, retrieve the percentage of remaining engine oil. Record the remaining engine oil life.

  2. Object Number: 21745  Size: SH
  3. Battery Disconnect Caution Disconnect the negative battery cable.
  4. Remove the PCM from the mounting hardware.
  5. Disconnect the harness connectors from the PCM.
  6. Remove the PCM from the engine compartment.

Installation Procedure

    Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 21745  Size: SH
  1. Connect the harness connectors to the PCM.
  2. Tighten
    Tighten the connectors to 8 N·m (71 lb in).

  3. Position and install the PCM into the vehicle.
  4. Connect the negative battery cable.
  5. The replacement PCM will NOT allow secondary air injection (AIR) pump operation until a total of 16 km (10 miles) have been accumulated.
  6. The new PCM must be programmed. Refer to Powertrain Control Module Programming .