Important: Never swap OnStar® vehicle integration units (VIU), or the vehicle communication units (VCU) from other vehicles. Transfer of OnStar® components from other vehicles should NOT be done. Each OnStar® component has a unique identification number. The VIU has a 10-digit specific station identification (STID) and the VCU has a 11-digit specific electronic serial number (ESN). These identification numbers are used by the National Cellular Telephone Network and OnStar® systems, and are stored in the General Motors vehicle history files by VIN.

1. Open the rear compartment lid.
2. Remove the forward rear compartment trim panel. Refer to Rear Compartment Trim Panel Replacement .
3. Disconnect the cellular coaxial cable (2) from the OnStar® VCU by pulling upward on the spring loaded snap connector.
4. Disconnect the electrical connector.
5. Remove the VCU (6) by lifting the retainer tab (1).
6. Remove the VCU (6).
7. The old VCU must be returned for core credit.

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



2. Install the OnStar® VCU (6) into the module bracket assembly.
3. Connect the electrical connector.
4. Connect the cellular coaxial cable (2) to the VCU (6) until fully seated.
5. Ensure the locking tab (1) is secure to the VCU.
6. Install the forward rear compartment trim panel. Refer to Rear Compartment Trim Panel Replacement .
7. Reconfigure the OnStar® system. Refer to OnStar Reconfiguration .

The 11-digit ESN number will be needed by the OnStar® advisor.

8. Close the rear compartment lid.