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Home >> Cadillac >> 2002 >> Escalade EXT >> Repair and Diagnosis >> External Pages >> Different car >> Section 1144 (Cellular Communication System) >> Repair Instructions >> OnStar Vehicle Interface Unit (VIU) Replacement >> Installation Procedure
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Installation Procedure

WARNING: This page is about a different car, the 2003 Pontiac Grand Prix. However, it is still accessible from the selected car via links, so may be relevant.
  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 Cautions and Notices.
  3. Install the OnStar® mounting bracket screws to the VIU.

    Tighten 

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

    Fig 1: Installing Mounting Screws To Vehicle Interface Unit
    G01503472Courtesy of GENERAL MOTORS CORP.
  4. Connect the GPS antenna cable to the VIU.
    Fig 2: Connecting Global Positioning System Antenna Cable To Vehicle Interface Unit
    G01503473Courtesy of GENERAL MOTORS CORP.
    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.
    Fig 3: Connecting Red 32-Way Connector To Vehicle Interface Unit
    G01503474Courtesy of GENERAL MOTORS CORP.
  6. Connect the blue 32-way connector to the VIU.
    Fig 4: Connecting Blue 32-Way Connector To Vehicle Interface Unit
    G01503475Courtesy of GENERAL MOTORS CORP.
  7. Position the VIU to the Inner wheel housing.
  8. Install the OnStar® mounting bracket nuts to the VIU/VCU bracket.

    Tighten 

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

    Fig 5: Installing Nuts To Vehicle Interface Unit
    G01503476Courtesy of GENERAL MOTORS CORP.
  9. Install the vehicle communication unit VCU. Refer to ONSTAR VEHICLE COMMUNICATION UNIT (VCU) REPLACEMENT  .

    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.

  10. Press and hold the white dot button until the OnStar® status LED turns from green to red, and back again to green.
  11. Install a scan tool. Use the ID information menu to access the new STID number.
  12. Move the vehicle to an open area that is away from tall buildings and with a clear view of unobstructed sky. Allow the vehicle to run for 10 minutes.
  13. Press the blue OnStar® button to connect to the OnStar® call center.
    1. 13.1. Tell the advisor that this vehicle has received a new VIU.
    2. 13.2. Ask the advisor to add the new STID to update the customer's account.
    3. 13.3. Follow any additional instructions from the OnStar® advisor.
    4. 13.4. Ask the advisor to activate the OnStar® personal calling feature, if available.
  14. Return the old VIU for core credit.
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