GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2001 🢒 Sonoma Pickup - 2WD 🢒 Body and Accessories 🢒 Cellular Communication 🢒 OnStar Vehicle Communication Unit Replacement

Removal Procedure

    Important: The vehicle communication unit (VCU) 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 top cover of the body side trim panel on the right side of the vehicle to expose the VCU/VIU assembly.

    2. Object Number: 655250 Size: SH
  2. Disconnect the cellular antenna coaxial cable (2) and electrical connector (6) from the VCU (7).
  3. Detach the steel retainer (8) to release the VCU (7) from the VCU/VIU assembly.
  4. Remove the VCU from the vehicle.
  5. The old VCU must be returned for core credit.

Installation Procedure
  1. Record the 11-digit ESN from the label on the new VCU module.

    2. Object Number: 655250 Size: SH
  2. Install the VCU (7) to the vehicle.
  3. Install the VCU (7) to the VCU/VIU assembly mounting bracket ensuring that the steel retainer (8) is securely fastened.
  4. Reconnect the cellular antenna coaxial cable (2) and electrical connector (6) to the VCU.
  5. Install the top cover of the body side trim panel to cover the VCU/VIU assembly.

    6. Important: After replacing the VCU, you must reconfigure the OnStar® system. Failure to reconfigure the system will result in an additional customer visit for repair.

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