Supplemental Restraints
5 LessonsAirbag systems, seatbelt pretensioners, and SRS safety procedures.
Overview
Supplemental Restraint Systems (SRS) save lives — and can injure technicians who do not respect them. This module covers airbag deployment, clockspring operation, seatbelt pretensioners, crash sensors, the SRS module, and the critical safety procedures required when working near any SRS component.
Key Components
- Airbag modules (frontal, side, curtain, knee)
- Clockspring
- Seatbelt pretensioners
- Crash sensors and SRS module
- Occupant detection system
How It Works
The SRS module monitors crash sensors throughout the vehicle. When a crash is detected that exceeds the deployment threshold, the module sends an electrical signal to the appropriate airbag inflators, which use a chemical reaction to rapidly inflate the airbag cushion. Seatbelt pretensioners fire simultaneously to tighten the belt.
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Join the Nation — FreeCommon Problems
- Clockspring failure causing airbag light and horn issues
- Passenger seat occupant sensor mat failure
- SRS light on after minor collision (crash data stored)
- Connector corrosion under seats from spills
- Seatbelt pretensioner replacement after deployment
Diagnostic Tips
- ALWAYS disable SRS before working near airbag components
- Wait manufacturer-specified time after disconnecting battery
- Clockspring failure often follows steering column work
- Resistance testing of SRS circuits — follow manufacturer procedure exactly
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