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 the PCM to be replaced, the PCM should be inspected first to see if the correct part is being used. If the correct part is being used, remove the faulty PCM and install the new service PCM.

Important: To prevent internal PCM damage, the ignition must be OFF when disconnecting or reconnecting power to the PCM. For example, when working with a battery cable, PCM pigtail, PCM fuse, or jumper cables.

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

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: 1284769  Size: SH
  3. Loosen the PCM harness connector bolts (4) from the center of the PCM harness connectors.
  4. Notice: In order to prevent internal damage to the PCM, the ignition must be OFF when disconnecting or reconnecting the PCM connector.

  5. Remove the PCM harness connectors (2) from the PCM (1).
  6. Remove the PCM retaining bolts (3) and nuts (6).
  7. 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.

  8. Slide the PCM (1) away from the intake manifold past the mounting studs (5) and remove PCM from the vehicle.
  9. Remove the PCM mounting studs (5) from the intake manifold ONLY if replacing the studs.

Installation Procedure

    Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 1284769  Size: SH
  1. Install the PCM mounting studs (5) to the intake manifold, if removed.
  2. Tighten
    Tighten the studs to 6 N·m (53 lb in).

  3. Install the PCM (1) onto the studs (5).
  4. Install the PCM retaining bolts (3).
  5. Tighten
    Tighten the bolts to 8 N·m (71 lb in).

  6. Install the PCM retaining nuts (6).
  7. Tighten
    Tighten the nuts to 8 N·m (71 lb in).

  8. Install the PCM harness connectors (2) to the PCM body.
  9. Tighten the PCM harness connector retaining bolts (4).
  10. Tighten
    Tighten the bolts to 8 N·m (71 lb in).

  11. If a new PCM is being installed, the PCM must be programmed. Refer to Service Programming System (SPS) in Programming.