GM Service Manual Online
For 1990-2009 cars only

Service of the powertrain control module (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 PCM is the correct part. If the PCM is faulty, remove the PCM and install the new service PCM.

The new service PCM will not be programmed. You must program the new PCM. Diagnostic trouble code (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.

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: 55493  Size: SH

    Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

  3. Disconnect the negative battery cable.
  4. Remove the screws from the air cleaner top cover.
  5. Remove the air cleaner top cover.

  6. Object Number: 186521  Size: SH
  7. Disconnect the harness connectors from the PCM.

  8. Object Number: 186523  Size: SH
  9. Remove the PCM from the air cleaner housing assembly.

Installation Procedure

    Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 186521  Size: SH
  1. Install the connectors to the PCM.
  2. Tighten
    Tighten the connectors to 8 N·m (71 lb in).

  3. Install the PCM into the air cleaner housing assembly.

  4. Object Number: 55493  Size: SH
  5. Install the air cleaner top cover.
  6. Connect the negative battery cable.
  7. The replacement PCM will NOT allow secondary air injection (AIR) pump operation until a total of 16.9 km (10 miles) have been accumulated.
  8. The new PCM must be programmed. Refer to Powertrain Control Module Programming .