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.


    Object Number: 1863833  Size: SH
  1. Using a scan tool, retrieve the percentage of remaining engine oil. Record the remaining engine oil life.
  2. Notice: In order to prevent internal damage to the PCM, the ignition must be OFF when disconnecting or reconnecting the PCM connector.

  3. Disconnect the instrument panel wiring harness electrical connector (1) from the PCM.

  4. Object Number: 1863834  Size: SH

    Notice: In order to prevent internal damage to the PCM, the ignition must be OFF when disconnecting or reconnecting the PCM connector.

  5. Disconnect the engine wiring harness electrical connectors (1) from the PCM.

  6. Object Number: 1863837  Size: SH

    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.

  7. Disengage the top 2 retainers and remove the PCM from the bracket.

  8. Object Number: 1863835  Size: SH
  9. If the PCM and bracket require removal, perform the following steps, otherwise proceed to step 4 in the installation procedure.
  10. Remove the PCM bracket bolts and nuts
  11. Remove the PCM bracket w/PCM from the studs.

Installation Procedure


    Object Number: 1863835  Size: SH
  1. If the PCM and bracket were removed, perform the following steps, otherwise proceed to step 4.
  2. Install the PCM bracket w/PCM to the studs.
  3. Notice: Refer to Fastener Notice in the Preface section.

  4. Install the PCM bracket bolts and nuts
  5. Tighten
    Tighten the bolts/nuts to 9 N·m (80 lb in).


    Object Number: 1863837  Size: SH
  6. Set the PCM into the bottom retainer on the bracket and push the PCM rearward, engaging the 2 top retainers.

  7. Object Number: 1863834  Size: SH

    Notice: In order to prevent internal damage to the PCM, the ignition must be OFF when disconnecting or reconnecting the PCM connector.

  8. Connect the engine wiring harness electrical connectors (1) to the PCM.

  9. Object Number: 1863833  Size: SH

    Notice: In order to prevent internal damage to the PCM, the ignition must be OFF when disconnecting or reconnecting the PCM connector.

  10. Connect the I/P wiring harness electrical connector (1) to the PCM.
  11. If a NEW PCM was installed, program the PCM. Refer to Control Module References .
  12. Using a scan tool, set the remaining engine oil life.