GM Service Manual Online
For 1990-2009 cars only

Service of the engine control module (ECM) (controller) should normally consist of either replacement of the ECM or electrically erasable programmable read only memory (EEPROM) programming. If the diagnostic procedures call for ECM replacement, inspect the ECM first to see if the ECM is the correct part. If the ECM is faulty, remove the ECM and install the new service ECM.

Caution: 

   • Turn the ignition OFF when installing or removing the control module connectors and disconnecting or reconnecting the power to the control module (battery cable, powertrain control module (PCM)/engine control module (ECM)/transaxle control module (TCM) pigtail, control module fuse, jumper cables, etc.) in order to prevent internal control module damage.
   • Control module damage may result when the metal case contacts battery voltage. DO NOT contact the control module metal case with battery voltage when servicing a control module, using battery booster cables, or when charging the vehicle battery.
   • In order to prevent any possible electrostatic discharge damage to the control module, do no touch the connector pins or the soldered components on the circuit board.
   • Remove any debris from around the control module connector surfaces before servicing the control module. Inspect the control module connector gaskets when diagnosing or replacing the control module. Ensure that the gaskets are installed correctly. The gaskets prevent contaminant intrusion into the control module.
   • The replacement control module must be programmed.

Note: When replacing the production ECM with a service ECM, it is important to transfer the broadcast code and production ECM number to the service ECM label. Do not record this information on the ECM cover. Transfer allows positive identification of ECM parts throughout the service life of the vehicle.

The new service ECM will not be programmed. You must program the new ECM. DTC P0602 indicates the ECM is not programmed or has malfunctioned.

There are no user serviceable parts in this ECM. The ECM should never be opened for any reason.

Note: 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.

Removal Procedure

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

  2. Object Number: 1544730  Size: SH
  3. Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection .
  4. Remove the left sheet metal diagonal brace. Refer to Front End Sheet Metal Diagonal Brace Replacement .
  5. Loosen the air cleaner cover screws and remove the cover (1) from the air cleaner assembly (3).
  6. Disconnect the engine harness electrical connectors (4) from the ECM.
  7. Remove the ECM (2) from the air cleaner cover.

Installation Procedure


    Object Number: 1544730  Size: SH
  1. Connect the engine harness electrical connectors (4) to the ECM.
  2. Install the ECM (2) to the air cleaner cover.
  3. Install the air cleaner assembly cover.
  4. Caution: Refer to Fastener Caution in the Preface section.

  5. Install the air cleaner cover (1) to the air cleaner assembly (3) and tighten the cover screws to 4 N·m (35 lb in) .
  6. Install the left sheet metal diagonal brace. Refer to Front End Sheet Metal Diagonal Brace Replacement .
  7. Connect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection .
  8. If a new ECM is being installed, program the EEPROM. Refer to Control Module References .