GM Service Manual Online
For 1990-2009 cars only

Notice: In order to prevent possible electrostatic discharge (ESD) damage to the VCM, do not touch the connector pins or soldered components on the circuit board.

Important: 

   • Service of the vehicle control module (VCM) consists of either replacement of the VCM or reprogramming of the VCM.
   • If the VCM is being replaced, the knock sensor (KS) module must be transferred to the replacement VCM.
   • The replacement VCM must be programmed before the vehicle will run.
   • The replacement VCM must have the Passlock Reprogramming procedure performed before the vehicle will run.
   • The replacement VCM must have the CKP System Variation Learn procedure performed or a DTC P1336 will set.

A shorted solenoid, relay coil, or harness will not damage the output driver module (ODM) in the VCM. A shorted solenoid, relay coil, or harness will cause the circuit and the controlled component to be inoperative.

When the circuit fault is not present or the technician has repaired the fault, the output driver module (ODM) will again operate in a normal manner due to its fault protected design.

Removal Procedure

    Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

  1. Disconnect the negative battery cable.

  2. Object Number: 308980  Size: SH

    Notice: In order to prevent possible electrostatic discharge (ESD) damage to the VCM, do not touch the connector pins or soldered components on the circuit board.

  3. Remove the spring retainers off the edges of the VCM.
  4. Slide the VCM out of the bracket at an angle.

  5. Object Number: 322822  Size: SH
  6. Remove the VCM harness connectors.

  7. Object Number: 279289  Size: SH

    Important: The remaining steps are only necessary for a VCM replacement.

  8. Remove the access cover screws.
  9. Remove the VCM access cover.

  10. Object Number: 10783  Size: SH

    Important: Since the Knock Sensor module will be used in the replacement VCM, place the module in an area where it will not be damaged.

  11. Gently pinch the retaining clip.

  12. Object Number: 279302  Size: SH
  13. Pull upward to remove the Knock Sensor module.

Installation Procedure

Important: Ensure that the VCM being installed is the original VCM, or that the replacement VCM service number is identical to the original VCM service number.

Steps 1-4 are only necessary for a new VCM installation:


    Object Number: 279302  Size: SH
  1. Align the notches of the Knock Sensor module with the notches in the Knock Sensor module socket.
  2. Important: Press only on the ends of the Knock Sensor module . Gently press on the Knock Sensor module until it is firmly seated in the socket. Listen for the click.

  3. Install the Knock Sensor module in the Knock Sensor module socket.

  4. Object Number: 279289  Size: SH
  5. Install the access cover on the VCM.
  6. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  7. Install the access cover screws.
  8. Tighten
    Tighten the access cover screws to 4.8 N·m (42 lb in).


    Object Number: 322822  Size: SH
  9. Connect the VCM harness connectors.

  10. Object Number: 308980  Size: SH
  11. Insert the VCM into the VCM bracket.
  12. Install the retaining springs over the edges of the VCM.
  13. Connect the negative battery cable.
  14. Program the new VCM.

VCM Programming

  1. Take the following steps in order to set-up for programming the VCM (EEPROM) .
  2. • The battery is fully charged.
    • The ignition is ON.
    • The Data Link Connector (DLC) is secure.
  3. Refer to an updated Techline terminal and follow the user's instructions for VCM programming.
  4. If the VCM fails to program, do the following functions:
  5. • Check all the VCM connections.
    • Check the ITCS terminal and equipment for the latest software version.
    • Try again to program the VCM. If the programming fails again, replace the VCM.
  6. Perform the Passlock Reprogramming Procedure. Refer to PASSLOCK Reprogramming Seed and Key in Theft Deterrent.
  7. Perform the CKP System Variation Learn Procedure. Refer to Crankshaft Position System Variation Learn .
  8. For a functional check, perform the Powertrain On-Board Diagnostic (OBD) System Check. Refer to Powertrain On Board Diagnostic (OBD) System Check .