GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1999 🢒 Corvette 🢒 Restraints 🢒 SIR 🢒 Inflatable Restraint Sensing and Diagnostic Module Replacement

Removal Procedure

    CAUTION: Be careful when you handle a sensing and diagnostic module (SDM). Do not strike or jolt the SDM. Before applying power to the SDM:

       • Remove any dirt, grease, etc. from the mounting surface
       • Position the SDM horizontally on the mounting surface
       • Point the arrow on the SDM toward the front of the vehicle
       • Tighten all of the SDM fasteners and SDM bracket fasteners to the specified torque value
    Failure to follow the correct procedure could cause air bag deployment, personal injury, or unnecessary SIR system repairs.

    Caution: If any water enters the vehicle's interior up to the level of the carpet or higher and soaks the carpet, the sensing and diagnostic module (SDM) and the SDM harness connector may need to be replaced. The SDM could be activated when powered, which could cause deployment of the air bag(s) and result in personal injury. Before attempting these procedures, the SIR system must be disabled. Refer to Disabling the SIR System.

    With the ignition OFF, inspect the SDM mounting area, including the carpet. If any significant soaking or evidence of significant soaking is detected, you must perform the following tasks:

    1. Remove all water.
    2. Repair the water damage.
    3. Replace the SDM harness connector.
    4. Replace the SDM.
    Failure to follow these tasks could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs.

  1. Disable the SIR system. Refer to Disabling the SIR System .
  2. Remove the accessory trim plate. Refer to Instrument Panel Accessory Trim Plate Replacement in Instrument Panel, Gauges and Console.
  3. Remove the heater control assembly. Refer to Control Assembly Replacement in HVAC Systems with A/C - Manual.

    4. Object Number: 391030 Size: SH
  4. Remove the connector position assurance (CPA) from the wire harness connector to the inflatable restraint sensing and diagnostic module (SDM).

    5. Object Number: 391032 Size: SH
  5. Disconnect the SDM harness connector from the SDM.

    6. Object Number: 391034 Size: SH
  6. Remove the SDM (3) mounting fasteners (2).
  7. Remove the SDM from the IP center support system (1).

Installation Procedure

    Object Number: 391034 Size: SH
  1. Install the SDM (3) to the IP center support system (1).

    2. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  2. Install the SDM mounting fasteners (2).

    3. Tighten
    Tighten fasteners to 10 N·m (89 lb in).


    Object Number: 391032 Size: SH
  3. Install the SDM harness connector to the SDM.

    4. Object Number: 391030 Size: SH
  4. Install the CPA to the SDM harness connector.
  5. Install the heater control assembly. Refer to Control Assembly Replacement in HVAC Systems with A/C - Manual.
  6. Install the accessory trim plate. Refer to Instrument Panel Accessory Trim Plate Replacement in Instrument Panel, Gauges and Console.

    7. Important: The AIR BAG indicator may remain ON after the SDM has been replaced. DTC B1001 may set requiring the SDM part number to be set in multiple modules. If the indicator remains ON after enabling the SIR system, perform the diagnostic system check and follow the steps thoroughly to ensure that the SDM is set properly.

  7. Enable the SIR system. Refer to Enabling the SIR System .