Airbag / SRS Safety and Diagnosis

Pyrotechnic safety systems: what you may test, and the rules that keep you alive.

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Safety notice

Airbags, pretensioners and their circuits are pyrotechnic. Never probe a live or deployed circuit, never drop or heat a module, and always disconnect the battery and respect the manufacturer wait time before working.

What you will learn

Describe SRS components
Follow safe working rules
Interpret SRS codes

The supplemental restraint system (SRS) includes airbags, seatbelt pretensioners, impact sensors, an occupancy/seat sensor and the SRS control module. Most faults are electrical: under-seat connectors, wiring damaged during interior work, or a sensor.

Because these are pyrotechnic devices, safety rules are absolute. Isolate the system per the manufacturer procedure, wait the specified time, and never use an ohmmeter on an airbag circuit in a way that could fire it.

Code area	Typical cause
Seat/occupancy	Under-seat connector, sensor
Pretensioner circuit	Wiring after interior work
Impact sensor	Sensor, wiring or mounting
Supply/communication	Power, ground or network to the module

Key points

Most SRS faults are wiring or connectors.
Safety procedure before any measurement.
The warning lamp staying on means at least one circuit failed its test.

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Key points

Airbags and pretensioners are pyrotechnic
Never probe live or deployed circuits
Disconnect power and wait per the manufacturer

All values shown are training examples. Real thresholds depend on the manufacturer, engine, temperature and system — always confirm with the vehicle service documentation.