What causes the airbag (SRS) warning light?

An illuminated airbag light means the SRS module has found a fault and disarmed part of the system. Some causes are cleared with a module reset; others need a part replaced first. Here are the common ones.

Common causes

Stored crash data after an accident

The most common reason a light won't clear: the module recorded a collision and locked itself. This is what an airbag module reset removes once the car is repaired.

A deployed seatbelt pretensioner

Pretensioners fire in many impacts. A blown pretensioner sets a fault and, like a deployed airbag, must be replaced — after which the module can be reset.

Clock spring / rotary coupler

The coiled contact behind the steering wheel that connects the driver's airbag can wear or break, throwing a fault. This is a mechanical part that needs replacing.

Loose or corroded connectors

Airbag connectors under the seats are a frequent culprit — moved seats, spilled drinks or corrosion break the circuit and light the lamp. Often fixed by cleaning or reseating the plug.

Seat occupancy sensor

The passenger seat sensor/mat can fail and disable the passenger airbag, lighting the SRS lamp.

Low battery or voltage events

A flat battery or jump-start can trigger faults across modules. On BMW and Mini this is also the classic trigger for FRM3 footwell module failure.

Which of these does a reset fix?

A module reset clears stored crash data and returns the control module to working order. Faults caused by a failed physical part — pretensioner, clock spring, sensor or wiring — need that part repaired first; the module can then be reset if it's still holding crash data.

Common questions