GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 1998 🢒 DeVille 🢒 Restraints 🢒 SIR 🢒 Inflatable Restraint Sensing and Diagnostic Module Replacement

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
  1. Disable the frontal SIR system. Refer to Disabling the SIR System .
  2. Remove the driver seat. Refer to Seat Replacement in Seats.
  3. Remove the sill plate (RH). Refer to Carpet Retainer Replacement in Seats.

    4. Object Number: 235763 Size: SH
  4. Lift up the carpet and insulation to access the inflatable restraint sensing and diagnostic module (SDM).
  5. Remove the Connector Position Assurance (CPA) (4) from the SDM harness connector (3).

    6. Object Number: 235758 Size: SH
  6. Disconnect the SDM harness connector (3) from the SDM (1).

    7. Object Number: 235751 Size: SH
  7. Remove the SDM mounting fasteners (6).
  8. Remove the SDM (1) from the floor sheetmetal (2).

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

  9. Use any of the following repair steps if any of these conditions exists:
  10. The SDM mounting bracket is broken loose from the floor sheetmetal at the weld.

    11. Repair by mig welding, using the puddle weld method the spots that have broken loose. Always weld the bracket in the same spots as the original welds.

  11. The SDM attachment nut is missing or broken.

    12. 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.

  12. Repair by slide a loose nut (P/N 11515741) under the SDM bracket. While you hold the nut in place, install the bolt (P/N 11515925).

    13. Tighten
    Tighten fasteners to 9 N·m (80 lb in).

  13. The SDM ground wire nut is missing.

    14. Repair by drilling the 8 mm (0.315 in) hole in the bracket to 12 mm (0.472 in). Tack weld a loose weld nut (P/N 20530601) to the bracket in place of the missing nut. Fasten the ground wire with the original bolt (P/N 3578880).

    Tighten
    Tighten fasteners to 6 N·m (54 lb in).

  14. The SDM attachment nut or ground nut is stripped.

    15. repair by drilling a 6.5 mm (0.256 in) hole through the weld nut. Use a new 7 mm bolt (P/N 10267482) to fasten the SDM or the ground wire.

    Tighten
    Tighten fasteners to 16 N·m (12 lb ft).

  15. The SDM attachment bolt or ground bolt is broken.

    16. Repair by using a tap, bolt remover or drill to remove the broken bolt. Drill a 6.5 mm (0.256 in) hole through the weld nut. Use a new 7 mm bolt (P/N 10267482) to fasten the SDM or the ground wire.

    Tighten
    Tighten fasteners to 16 N·m (12 lb ft).

Installation Procedure

    Object Number: 235751 Size: SH
  1. Install the SDM (1) to the floor sheetmetal (2).

    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 (6).

    3. Tighten
    Tighten fasteners to 9 N·m (80 lb in).


    Object Number: 235758 Size: SH
  3. Install the SDM harness connector (3) to the SDM (1).

    4. Object Number: 235763 Size: SH
  4. Install the Connector Position Assurance (CPA) (4) to the SDM harness (3) connector.
  5. Install the sill plate (RH). Refer to Carpet Retainer Replacement in Seats.
  6. Install the driver seat. Refer to Seat Replacement in Seats.
  7. Enable the frontal SIR system. Refer to Enabling the SIR System .