GM Service Manual Online
For 1990-2009 cars only

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.

Removal Procedure


    Object Number: 381863  Size: SH
  1. Disable the SIR system. Refer to Disabling the SIR System .
  2. Remove the front passenger seat. Refer to Seat Replacement in Seats.
  3. Remove or lift up the carpet from the vehicle. Refer to Floor Panel Carpet Replacement in Interior Trim.
  4. Lifting the carpet and insulation will gain access to the inflatable restraint sensing and diagnostic module (SDM).

  5. Object Number: 661777  Size: SH
  6. Remove both wiring harness connectors (3) that link the Connector Position Assurance (CPA) (1) to the SDM .
  7. Disconnect both wiring harness connectors (3) from the SDM (2).

  8. Object Number: 661780  Size: SH
  9. Remove the SDM mounting fasteners (2).
  10. Remove the SDM (1) from the vehicle floor (3).

Installation Procedure


    Object Number: 661780  Size: SH
  1. Install the SDM (1) to the vehicle floor (3).
  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.

  3. Install SDM mounting fasteners (2).
  4. Tighten
    Tighten the fasteners to 9 N·m (80 lb in).


    Object Number: 661777  Size: SH
  5. Connect both wiring harness connectors (3) to the SDM (2).
  6. Install both wiring harness connectors (3) from the CPA (1) to the SDM .

  7. Object Number: 381863  Size: SH
  8. Install the carpet into the vehicle. Refer to Floor Panel Carpet Replacement in Interior Trim.
  9. Install the front passenger seat. Refer to Seat Replacement in Seats.
  10. Enable the SIR system. Refer to Enabling the SIR System .
  11. 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.

  12. Reprogram the BCM. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System.