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, inspect the PCM first to see if the 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. DTC P0602 indicates the EEPROM is not programmed or has malfunctioned.

Notice: In order to prevent possible electrostatic discharge damage to the PCM, do not touch the connector pins or soldered components on the circuit board.

There are no user serviceable parts in this PCM. The PCM should never be opened for any reason.

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, you must transfer the broadcast code and production PCM number to the service PCM label. DO NOT record the information on the PCM cover. This will allow positive identification of the 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: 289623  Size: SH
  3. Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
  4. Remove the air cleaner assembly (4). Refer to Air Cleaner Assembly Replacement .

  5. Object Number: 256272  Size: SH
  6. Disconnect the PCM harness connectors (2) from the PCM (1).
  7. Remove the PCM (1) from the lower air cleaner housing.

Installation Procedure

    Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 256272  Size: SH
  1. Install the PCM harness connectors (2) to the PCM (1).
  2. Tighten
    Tighten the connector fastener to 8 N·m (71 lb in).


    Object Number: 256270  Size: SH
  3. Install the PCM (3) into the lower air cleaner housing.
  4. Install the air cleaner assembly.
  5. Connect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
  6. If a new PCM is being installed, program the PCM. Refer to Powertrain Control Module Programming .