GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2003 🢒 CTS - RHD 🢒 Engine 🢒 Engine Electrical 🢒 Engine Control Module Replacement

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.

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

  2. Turn OFF the ignition.

    3. Object Number: 785849 Size: SH
  3. Remove the screw (2) securing the engine control module (ECM) ground wire (1) to the ECM (3).

    4. Object Number: 785823 Size: SH

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

  4. Flip the release levers to the open position (3) and disconnect the ECM connectors (2) from the ECM (5).

    5. Object Number: 785824 Size: SH
  5. Remove the nuts securing the ECM to the ECM bracket.
  6. Remove the ECM from the ECM bracket.

Installation Procedure


    Object Number: 785824 Size: SH
  1. With the ignition off, position the ECM to the ECM bracket.

    2. Notice: Refer to Fastener Notice in the Preface section.

  2. Install the nuts securing the ECM to the ECM bracket.

    3. Tighten
    Tighten the ECM nuts to 8 N·m (71 lb in).


    Object Number: 785823 Size: SH
  3. Carefully align the harness connectors (2) with the ECM connectors.
  4. Guide the connectors (2) into place while moving the release levers to the locked position (1).

    5. Object Number: 785849 Size: SH
  5. Install the screw (2) securing the ECM ground wire (1) to the ECM (3).

    6. Tighten
    Tighten the ECM ground wire screw to 4.5 N·m (40 lb in).

  6. Program the ECM. Refer to Service Programming System (SPS) in Programming.

    7. Important: When replacing a ECM with a GM SPO Replacement Part, the new ECM will learn the incoming fuel continue password immediately after programming and upon receipt of a password message. Once a password message is received and a password is learned, perform the learn procedure to change this password again. A ECM which had been installed in another vehicle will have learned the fuel continue password of the other vehicle's theft deterrent control module. Perform either the 10-minute relearn procedure or the 30-minute relearn procedure after programming to learn the fuel continue password of the current vehicle's theft deterrent control modules.

  7. Program the theft deterrent system components if the ECM was installed from another vehicle. Refer to Programming Theft Deterrent System Components in Theft Deterrent.
  8. Perform the idle learn procedure. Refer to Idle Learn .