GM Service Manual Online
For 1990-2009 cars only

Caution: Proper operation of the SIR sensing system requires that any repairs to the vehicle structure return the vehicle structure to the original production configuration. Not properly repairing the vehicle structure could cause non-deployment in a collision or deployment for conditions less severe than intended.

    • If any supplemental inflatable restraints (SIR) components are damaged, they must be replaced. If SIR components mounting points are damaged, they must be repaired or replaced.
    • Never use SIR parts from another vehicle. This does not include remanufactured parts purchased from an authorized source.
    • Do not attempt to service the sensing and diagnostic module (SDM), the steering wheel module coil, or other air bag modules. These items must be replaced if they are defective.
    • Verify the part number of replaced air bag modules. Some inflator modules look identical but contain different internal components.

Accident with Deployment Component Replacements

All SIR components must be replaced after a frontal crash involving air bag deployment. After deployment, a powdery residue may be on the surface of the air bag. The powder consists primarily of cornstarch, used to lubricate the bag as it inflates, and by-products of the chemical reaction. The sodium hydroxide then quickly reacts with atmospheric moisture and is converted to sodium bicarbonate, also known as baking soda. Therefore, it is unlikely that sodium hydroxide will be present after deployment. Replace the following SIR components.

Caution: Safety precautions must be followed when handling a deployed inflator module (air bag). After deployment, the inflator module (air bag) surface may contain a small amount of sodium hydroxide, a by-product of the deployment reaction, that is irritating to the skin and eyes. Most of the powder on the inflator module (air bag) is harmless. as a precaution, wear gloves and safety glasses when handling a deployed inflator module (air bag), and wash your hands with mild soap and water afterwards.

    • The SDM
    • Air bag modules (as needed) and pretensioners
    • SIR wiring
    • Clock spring

Accident without Deployment Component Inspection

The following inspections must be performed after any crash, whether the air bag has deployed or not:

    • The steering column must be dimensionally inspected.
    •  Inspect the knee bolsters and mounting points for distortion, bending and cracking or other damages.
    • Inspect the instrument panel (I/P) and steering column reinforcement plate for distortion, bending and cracking or other damage.
    • Inspect the I/P braces for distortion, bending and cracking or other damage.
    • Inspect the seat belt and mounting points. Refer to Seat Belt System Description and Operation .