GM Service Manual Online
For 1990-2009 cars only

Communication Interface Module Replacement Late Production(F1) OnStar

Removal Procedure

    Important: The vehicle communication interface module (VCIM) has a specific set of unique numbers that tie the module to each vehicle. These numbers, the 10-digit station identification and the 11-digit electronic serial number, are used by the National Cellular Network and OnStar® to identify the specific vehicle. Because these numbers are tied to the vehicle identification number of the vehicle, you must never exchange these parts with those of another vehicle.

  1. Remove the rear compartment trim. Refer to Rear Compartment Trim Panel Replacement .

  2. Object Number: 794800  Size: SH
  3. Disconnect the antenna (2) and electrical connections (3) from the vehicle communication interface module (VCIM) (4).
  4. Release the VCIM retaining tabs (1).
  5. Slide the vehicle VCIM (4) out of the electrical component mounting bracket.

Installation Procedure


    Object Number: 794800  Size: SH
  1. When replacing the VCIM, record the 11-digit electronic serial number (ESN) and the 10-digit station identification (STID) number from the label on the new VCIM (4).
  2. Slide the VCIM (4) into the electrical component mounting bracket.
  3. Push in on the top of the VCIM (4) until an audible click is heard, indicating the retaining tabs (1) have securely fastened the VCIM (4) to the electrical component mounting bracket.
  4. Connect the antenna cable (2) and electrical connections (3) to the VCIM (4).
  5. Install the rear compartment trim. Refer to Rear Compartment Trim Panel Replacement .
  6. Important: After replacing the vehicle communication interface module, you must reconfigure the OnStar® system. Failure to reconfigure the system will result in an additional customer visit for repair. In addition, pressing and holding the white dot button on the keypad will NOT reset this version of the OnStar® system. This action will cause a DTC to set.

  7. Reconfigure the OnStar® system. Refer to OnStar Reconfiguration .