GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2001 🢒 Aztek - FWD 🢒 Body and Accessories 🢒 Cellular Communication 🢒 OnStar Vehicle Interface Unit Replacement

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 right insulator panel. Refer to Instrument Panel Insulator Panel Replacement - Right Side .
  2. Remove the instrument panel (I/P) compartment. Refer to Instrument Panel Compartment Replacement .

    3. Object Number: 725615 Size: SH
  3. Remove the screws securing the VIU bracket to the I/P metal brace.

    4. Object Number: 725713 Size: SH
  4. Disconnect the red 32-way electrical connectors and the blue 32-way electrical connector.
  5. Disconnect the global position system (GPS) cables from the VIU.

    6. Object Number: 725703 Size: SH
  6. Remove the VIU from the bracket by rotating the module upwards to release the hook tab.
  7. The old VIU must be returned for core credit.

Installation Procedure
  1. Record the 10-digit STID number from the label on the new module.

    2. Object Number: 725703 Size: SH
  2. Install the VIU to the bracket by rotating downwards into the hook tab.
  3. Connect the GPS cables to the VIU.

    4. Object Number: 725713 Size: SH
  4. Connect the red 32-way electrical connectors and the blue 32-way electrical connector.

    5. Notice: Refer to Fastener Notice in the Preface section.


    Object Number: 725615 Size: SH
  5. Install the screws securing the VIU bracket to the I/P metal brace.

    6. Tighten
    Tighten the screws to 10 N·m (89 lb in).

  6. Install the I/P compartment. Refer to Instrument Panel Compartment Replacement .
  7. Install the right insulator panel. Refer to Instrument Panel Insulator Panel Replacement - Right Side .

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

  8. Reconfigure the OnStar® system. Refer to OnStar Reconfiguration .
  9. Return the old VIU for core credit.