Removal Procedure

Important:  The vehicle interface unit (VIU) 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 VCU from the VIU. Refer to ONSTAR VEHICLE COMMUNICATION UNIT (VCU) REPLACEMENT  .
   Fig 1: Removing Nuts From Vehicle Interface Unit

   Courtesy of GENERAL MOTORS CORP.
2. Remove the nuts from the VIU/VCU bracket.
3. Remove the VIU from the inner wheel housing.
4. Disconnect the global positioning system (GPS) antenna cable from the VIU.
   Fig 2: Disconnecting Global Positioning System Antenna Cable From Vehicle Interface Unit

   Courtesy of GENERAL MOTORS CORP.
5. Disconnect the red 32-way connector from the VIU.
   Fig 3: Disconnecting Red 32-Way Connector From Vehicle Interface Unit

   Courtesy of GENERAL MOTORS CORP.
6. Disconnect the blue 32-way connector from the VIU.
   Fig 4: Disconnecting Blue 32-Way Connector From Vehicle Interface Unit

   Courtesy of GENERAL MOTORS CORP.
7. Remove the mounting screws from the VIU.
8. Remove the VIU from the VIU/VCU bracket.
9. The old VIU must be returned for core credit.
   Fig 5: Removing Mounting Screws From Vehicle Interface Unit

   Courtesy of GENERAL MOTORS CORP.