2007 Buick LaCrosse V6-3.6LFACTORY OEM SERVICE PROCEDURE

Engine Control Module: Service and Repair



Engine Control Module Replacement

Notice:
* 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.

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.

Removal Procedure

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

Factory service manual diagram



2. Turn the ignition OFF.

Important: Ensure that there is no main relay circuit voltage (ECM Fuse).

3. Use a DVOM in order to measure the main relay circuit voltage at the engine control module (ECM) fuse in the underhood fuse block. Refer to Electrical Center Identification Views.
4. Disconnect the battery negative cable.
5. Remove the ECM fuse in the underhood fuse block.
6. Remove the TCM/IPC fuse in the underhood fuse block.
7. Remove the ECM/TCM fuse in the underhood fuse block.
8. Unlock the body side (outboard) ECM electrical connector.

1. Depress the ECM electrical connector lever lock (1).
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.

Factory service manual diagram



9. Remove the body side (outboard) ECM connector.

Factory service manual diagram



10. Unlock and remove the engine side (inboard) ECM connector.

Factory service manual diagram



11. Remove the ECM redundant ground wire and bolt from the ECM.

Factory service manual diagram



12. Remove the ECM bolts.
13. Remove the ECM.

Factory service manual diagram



14. If necessary, perform the following steps:

1. Remove the ECM bracket bolts.
2. Remove the ECM bracket (1).

Installation Procedure

Factory service manual diagram



1. Install the ECM bracket, as necessary.

Notice: Refer to Fastener Notice in Service Precautions.

2. Install the ECM bracket bolts.

Tighten the ECM bracket bolts to 10 N.m (89 lb in).

Factory service manual diagram





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

3. Install the ECM.
4. Install the ECM bolts.

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

Factory service manual diagram



5. Install the ECM redundant ground and bolt to the ECM.

Tighten the ECM redundant ground wire bolt to 5 N.m (44 lb in).

Factory service manual diagram



6. Install the engine side (inboard) ECM connector.

Factory service manual diagram



7. Install the body side (outboard) ECM connector.
8. Install the ECM/TCM fuse in the underhood fuse block.
9. Install the TCM/IPC fuse in the underhood fuse block.
10. Install the ECM fuse in the underhood fuse block.
11. Connect the battery negative cable to the battery
12. Program the ECM. Refer to Control Module References in Computer/Integrating Systems. Programming and Relearning
13. Turn OFF the ignition for at least 5 seconds after the programming event is complete.

Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.

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