Onstar Vehicle Interface Unit (Viu) Replacement

IMPORTANT: Never exchange OnStar(R) vehicle integration units (VIU), or the vehicle communication units (VCU) from other vehicles. Transfer of OnStar(R) components from other vehicles should NOT be done. Each OnStar(R) 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(R) systems, and are stored in the General Motors vehicle history files by VIN.

REMOVAL PROCEDURE




1. Remove the VCU from the VIU. Refer to OnStar Vehicle Communication Unit (VCU) Replacement.
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.

NOTE: In order to avoid damage to the circuit board, do NOT over-tighten the thumb screws. Using your fingers, apply only a light pressure.




5. Disconnect the red 32-way connector from the VIU.




6. Disconnect the blue 32-way connector from the VIU.




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.

INSTALLATION PROCEDURE




1. Record the 10-digit STID number from the label on the VIU module.
2. Position the VIU to the VIU/VCU bracket.

NOTE: Refer to Fastener Notice in Service Precautions.

3. install the OnStar(R) mounting bracket screws to the VIU.

Tighten
Tighten the screws to 2 N.m (18 lb in).




4. Connect the GPS antenna cable to the VIU.

NOTE: In order to avoid damage to the circuit board, do NOT over-tighten the thumb screws. Using your fingers, apply only a light pressure.




5. Connect the red 32-way connector to the VIU.




6. Connect the blue 32-way connector to the VIU.




7. Position the VIU to the inner wheel housing.
8. Install the OnStar(R) mounting bracket nuts to the VIU/VCU bracket.

Tighten
Tighten the bracket nuts to 3 N.m (27 lb in).

9. Install the vehicle communication unit VCU. Refer to OnStar Vehicle Communication Unit (VCU) Replacement.
10. Contact the OnStar(R) Dealer Support line by pressing the OnStar(R) button twice.
The 10-digit STID number recorded will be needed by the OnStar(R) Dealer Support line.
11. The Old VIU must be returned for core credits.