GM Service Manual Online
For 1990-2009 cars only

Engine control module (ECM) service should normally consist of either ECM replacement or electrically erasable programmable read only memory (EEPROM) programming. If the diagnostic procedures require ECM replacement, check the ECM first to see if the correct part is being used.

Important: In order to prevent internal ECM damage, the ignition must be OFF when you disconnect or reconnect the power to the ECM. For example, disconnect the power when you work with the following components:

    • A battery cable
    • The ECM pigtail
    • The ECM fuse
    • The jumper cables

Important: 

   • When you diagnose or replace the ECM, remove any debris from the ECM connector surfaces before servicing the ECM module connector gaskets. Ensure that the gaskets are installed correctly. The gaskets prevent intrusion into the ECM.
   • The replacement ECM MUST be programmed.

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 percent. If the replacement module is not programmed with the remaining engine oil life, the engine oil will need to be changed at 5 000 km (3,000 mi) from the last engine oil change.


    Object Number: 1868651  Size: SH
  1. Using a scan tool, retrieve the percentage of remaining engine oil. Record the remaining engine oil life.
  2. Remove the wheelhouse filler panel. Refer to Front Wheelhouse Liner Replacement.
  3. Disconnect the engine wiring harness electrical connectors (1) from the ECM.
  4. Remove the ECM bolts (2).
  5. Remove the ECM.

Installation Procedure


    Object Number: 1868651  Size: SH
  1. Position the ECM.
  2. Notice: Refer to Fastener Notice in the Preface section.

  3. Install the ECM bolts (2).
  4. Tighten
    Tighten the bolts to 10 N·m (89 lb in).

  5. Connect the engine wiring harness electrical connectors (1) to the ECM.
  6. Install the wheelhouse filler panel. Refer to Front Wheelhouse Liner Replacement.
  7. If a new ECM is being installed, program the ECM. Refer to Control Module References.
  8. Warning: Replacement or reprogramming of the ECM, or replacement of the clutch pedal position sensor (CPPS) or clutch pedal requires that a CPPS learn procedure be performed. Failure to perform the CPPS learn procedure may result in personal injury or damage to the vehicle or its components if the vehicle is in gear and the starter motor is accidentally engaged.

  9. If equipped with a manual transmission, perform the clutch pedal position sensor learn procedure. Refer to Clutch Pedal Position Sensor Learn.