GM Service Manual Online
For 1990-2009 cars only

Removal Procedure

Notice: Always turn the ignition off when installing or removing the ECM connectors in order to prevent damage to the components.

    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.

    Important: It is necessary to record the remaining automatic transmission fluid life. If the replacement module is not programed with the remaining automatic transmission fluid life, the automatic transmission fluid life will default to 100%. If the replacement module is not programmed with the remaining automatic transmission fluid life, the automatic transmission fluid will need to be changed at 83000 km (50,000 mi) from the last automatic transmission fluid change.

  1. Using a scan tool, retrieve the percentage of remaining engine oil and the remaining automatic transmission fluid life. Record the remaining engine oil and the remaining automatic transmission fluid life.

  2. Object Number: 1285259  Size: SH
  3. Turn the ignition OFF.
  4. Important: Ensure that there is no main relay circuit voltage (ECM Fuse).

  5. Use a DVOM in order to measure the main relay circuit voltage at the ECM fuse in the underhood fuse block. Refer to Electrical Center Identification Views in Wiring Systems.
  6. Disconnect the battery negative cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
  7. Remove the ECM fuse in the underhood fuse block. Refer to Electrical Center Identification Views in Wiring Systems.
  8. Remove the TCM/IPC fuse in the underhood fuse block. Refer to Electrical Center Identification Views in Wiring Systems.
  9. Remove the ECM/TCM fuse in the underhood fuse block. Refer to Electrical Center Identification Views in Wiring Systems.
  10. Unlock the chassis side (upper) ECM electrical connector.
  11. 8.1. Depress the ECM electrical connector lever lock (1).
    8.2. Simultaneously rotate the ECM connector clamp lever and depress the lock slide (2).

    Notice: In order to prevent any possible electrostatic discharge damage to the ECM, do not touch the connector pins.


    Object Number: 1343429  Size: SH
  12. Remove the body side (upper) ECM connector.

  13. Object Number: 945720  Size: SH
  14. Unlock and remove the engine side (lower) ECM connector.

  15. Object Number: 1343434  Size: SH
  16. Remove the ECM redundant ground wire and bolt (2) from the ECM.

  17. Object Number: 887860  Size: SH
  18. Remove the ECM bolts.
  19. Remove the ECM.
  20. If you are replacing the ECM bracket, perform the following steps:

  21. Object Number: 945521  Size: SH
  22. Remove the electrical connector bracket and bolt from the ECM bracket.

  23. Object Number: 945670  Size: SH
  24. Remove the ground wire and bolt from the ECM bracket.

  25. Object Number: 945513  Size: SH
  26. Remove the wire harness retainer and bolt from the side of the ECM bracket.

  27. Object Number: 887861  Size: SH
  28. Remove the ECM bracket bolts (2 and 3).
  29. Remove the ECM bracket  (1).

Installation Procedure


    Object Number: 887861  Size: SH
  1. Install the ECM bracket (1).
  2. Notice: Refer to Fastener Notice in the Preface section.

  3. Install the ECM bracket bolts (2 and 3).
  4. Tighten

    1. Tighten the ECM bracket bolt (2) to 10 N·m (89 lb in).
    2. Tighten the ECM bracket bolts (3) to 23 N·m (17 lb ft).

    Object Number: 945513  Size: SH
  5. Install the wire harness retainer and bolt (2) to the side of the ECM bracket.
  6. Tighten
    Tighten the wire harness retainer bolt to 23 N·m (17 lb ft).


    Object Number: 945521  Size: SH
  7. Install the electrical connector bracket and bolt to the ECM bracket.
  8. Tighten
    Tighten the electrical connector bracket bolt to 10 N·m (89 lb in).


    Object Number: 1343434  Size: SH
  9. Install the wiring harness ground wire and bolt to the ECM bracket.
  10. Tighten
    Tighten the wiring harness ground wire bolt 10 N·m (89 lb in).


    Object Number: 887860  Size: SH

    Notice: In order to prevent any possible electrostatic discharge damage to the ECM, do not touch the connector pins.

  11. Install the ECM.
  12. Install the ECM bolts.
  13. Tighten
    Tighten the ECM bolts to 10 N·m (89 lb in).


    Object Number: 1343434  Size: SH
  14. Install the ECM redundant ground and bolt  (2) to the ECM.
  15. Tighten
    Tighten the ECM redundant ground wire bolt to 5 N·m (44 lb in).


    Object Number: 945720  Size: SH
  16. Install the engine side (lower) ECM connector.

  17. Object Number: 1343429  Size: SH
  18. Install the body side (upper) ECM connector.
  19. Install the ECM/TCM fuse in the underhood fuse block. Refer to Electrical Center Identification Views in Wiring Systems.
  20. Install the TCM/IPC fuse in the underhood fuse block. Refer to Electrical Center Identification Views in Wiring Systems.
  21. Install the ECM fuse in the underhood fuse block. Refer to Electrical Center Identification Views in Wiring Systems.
  22. Connect the battery negative cable to the battery. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
  23. Program the ECM. Refer to Service Programming System (SPS) in Programming.
  24. If you encounter an ECM programming error, with a display message of "Starting Disabled, Remove Key" on the driver information center, with a diagnostic test code (DTC) of P1631, perform the "10-Minute Relearn Procedure" found in Programming Theft Deterrent System Components. Refer to Programming Theft Deterrent System Components . Additional information can be found in service bulletin number 05524 A.
  25. Turn OFF the ignition for at least 5 seconds after the programming event is complete.
  26. Perform the idle learn procedure. Refer to Idle Learn .
  27. Use the scan tool to clear all DTCs.