GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2008 🢒 SLS 🢒 Diagnostic Navigation 🢒 Vehicle Diagnostic Information 🢒 Engine Control Module Replacement

Removal Procedure

    Object Number: 1285259 Size: SH
  1. Turn the ignition OFF.

    2. 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.
       • 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 percent. If the replacement module is not programmed with the remaining automatic transmission fluid life, the automatic transmission fluid will need to be changed at 83 000 km (50,000 mi) from the last automatic transmission fluid change.

  2. 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.
  3. 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.
  4. Disconnect the battery negative cable. Refer to Battery Negative Cable Disconnection and Connection.
  5. Remove the ECM fuse in the underhood fuse block. Refer to Electrical Center Identification Views .
  6. Remove the TCM/IPC fuse in the underhood fuse block. Refer to Electrical Center Identification Views.
  7. Remove the ECM/TCM fuse in the underhood fuse block. Refer to Electrical Center Identification Views.
  8. Unlock the chassis side (upper) engine control module electrical connector.
    9. 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
  9. Remove the body side (upper) ECM connector.

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

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

    12. Object Number: 887860 Size: SH
  12. Remove the ECM bolts.
  13. Remove the ECM.

    14. Object Number: 945521 Size: SH
  14. If you are replacing the ECM bracket, remove the electrical connector bracket and bolt from the ECM bracket.

    15. Object Number: 945670 Size: SH
  15. Remove ground bolt (1) and wire from the ECM bracket.

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

    17. Object Number: 887861 Size: SH
  17. Remove the ECM bracket bolts (2 and 3).
  18. 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.

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

    3. Tighten

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

    Object Number: 945513 Size: SH
  3. Install the wire harness retainer and bolt (2) to the side of the ECM bracket.

    4. Tighten
    Tighten the bolts to 23 N·m (17 lb ft).


    Object Number: 945521 Size: SH
  4. Install the electrical connector bracket and bolt to the ECM bracket.

    5. Tighten
    Tighten the bolts to 10 N·m (89 lb in).


    Object Number: 1343434 Size: SH
  5. Install the wiring harness ground wire and bolt (1) to the ECM bracket.

    6. Tighten
    Tighten the bolts to 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.

  6. Install the ECM.
  7. Install the ECM bolts.

    8. Tighten
    Tighten the bolts to 10 N·m (89 lb in).


    Object Number: 1343434 Size: SH
  8. Install the ECM redundant ground and bolt  (2) to the ECM.

    9. Tighten
    Tighten the bolt to 5 N·m (44 lb in).


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

    10. Object Number: 1343429 Size: SH
  10. Install the body side (upper) ECM connector.
  11. Install the ECM/TCM fuse in the underhood fuse block. Refer to Electrical Center Identification Views.
  12. Install the TCM/IPC fuse in the underhood fuse block. Refer to Electrical Center Identification Views.
  13. Install the ECM fuse in the underhood fuse block. Refer to Electrical Center Identification Views.
  14. Connect the battery negative cable to the battery. Refer to Battery Negative Cable Disconnection and Connection.
  15. Program the ECM. Refer to Control Module References.
  16. Turn OFF the ignition for at least 5 seconds after the programming event is complete.