GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2005 🢒 Envoy XUV 🢒 Engine 🢒 Engine Controls - 4.2L 🢒 Powertrain Control Module Replacement

Service of the powertrain control module (PCM) should normally consist of either replacement of the PCM or electrically erasable programmable read only memory (EEPROM) programming. If the diagnostic procedures call for the PCM to be replaced, the PCM should be inspected first to see if the correct part is being used. If the correct part is being used, remove the faulty PCM and install the new service PCM.

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.

    2. Object Number: 1284769 Size: SH
  2. Loosen the PCM harness connector bolts (4) from the center of the PCM harness connectors.

    3. Notice: In order to prevent internal damage to the PCM, the ignition must be OFF when disconnecting or reconnecting the PCM connector.

  3. Remove the PCM harness connectors (2) from the PCM (1).
  4. Remove the PCM retaining bolts (3) and nuts (6).

    5. Notice: Do not touch the connector pins or soldered components on the circuit board in order to prevent possible electrostatic discharge (ESD) damage to the PCM.

  5. Slide the PCM (1) away from the intake manifold past the mounting studs (5) and remove PCM from the vehicle.
  6. Remove the PCM mounting studs (5) from the intake manifold only if replacing the studs.

Installation Procedure

    Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 1284769 Size: SH
  1. Install the PCM mounting studs (5) to the intake manifold, if removed.

    2. Tighten
    Tighten the studs to 6 N·m (53 lb in).

  2. Install the PCM (1) onto the studs (5).
  3. Install the PCM retaining bolts (3).

    4. Tighten
    Tighten the bolts to 8 N·m (71 lb in).

  4. Install the PCM retaining nuts (6).

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

  5. Install the PCM harness connectors (2) to the PCM body.
  6. Tighten the PCM harness connector retaining bolts (4).

    7. Tighten
    Tighten the bolts to 8 N·m (71 lb in).

  7. If a new PCM is being installed, the PCM must be programmed. Refer to Control Module References .