For 1990-2009 cars

Callout | Component Name
--- | ---

#### Preliminary Procedure

Remove the left rear quarter lower trim panel. Refer to Quarter Lower Rear Trim Panel Replacement.

1 | Communication Interface Module

#### Procedure

1. Disconnect the electrical connectors.
2. When replacing the communication interface module be sure to transfer Bluetooth Antenna, if equipped.
3. Reprogram the communication interface module if replaced. Refer to Control Module References.
4. 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.

Tip

• | 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.

• | 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.