GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1999 🢒 Astro - 2WD 🢒 Body and Accessories 🢒 Wiring Systems 🢒 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. Refer to Disabling the SIR System .
  2. Remove the driver seat. Refer to Bucket Seat Replacement in Seats.
  3. Remove the sill trim molding from the left carpet retaining. Refer to Carpet Retainer Replacement in Interior Trim.
  4. Fold back the carpet to access the inflatable restraint sensing and diagnostic module (SDM).

    5. Object Number: 388351 Size: SH
  5. Remove the connector position assurance (CPA) (3) from the inflatable restraint sensing and diagnostic module (SDM) harness connector.
  6. Disconnect the SDM harness connector (2) from the SDM.
  7. Remove the SDM mounting fasteners (1).
  8. Remove the SDM (4) from the vehicle (5).

    9. Important: The following repair procedures should only be used in the event that the inflatable restraint sensing and diagnostic module (SDM) mounting studs or fasteners are damaged to the extent that the SDM may no longer be properly mounted.

  9. Repair the fasteners using the following procedure:
    10. 9.1. Remove the stripped nut and discard the nut.
    9.2. Drill out the weld spots to the weld stud from the floor pan side, then remove and discard the stud.
    9.3. Condition the floor panel attaching surface where the new stud is to be installed.
    9.4. Install new weld stud GM P/N 115115602 and clamp the weld stud.
    9.5. Migweld the stud at the drilled holes from above or below the floor pan, as required.
    9.6. Apply body sealer GM P/N 9984248 around any exposed openings.
    9.7. Install a new fastener GM P/N 11515933.

Installation Procedure

    Object Number: 388351 Size: SH
  1. Install the SDM (4) to the vehicle (5).

    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 (1).

    3. Tighten
    Tighten fasteners to 12 N·m (106 lb in).

  3. Install the SDM harness connector (2) to the SDM (4).
  4. Install the CPA (3) to the SDM harness connector (2).
  5. Position the carpet to cover the SDM.
  6. Install the left carpet retaining sill trim molding. Refer to Carpet Retainer Replacement in Interior Trim.
  7. Install the driver seat. Refer to Bucket Seat Replacement in Seats.

    8. 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.

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