Why is my airbag warning light on?
The airbag (SRS — Supplemental Restraint System) warning light indicates a fault in the airbag or seatbelt pretensioner system. When this light is on, your airbags may not deploy correctly in a collision — this is a safety-critical fault. Common causes include a faulty clock spring (the coil in the steering column), a failing seatbelt pretensioner, a disconnected sensor, or a depleted backup battery. Do not buy or drive a car with an active airbag warning light without having it diagnosed first.
Likely causes
Faulty clock spring (spiral cable)
The coil contact in the steering column that maintains electrical connection as the wheel turns — common failure point
Seatbelt pretensioner fault
Seatbelt tensioner circuits flag as faults; sometimes triggered by accident history
Airbag sensor fault
Impact sensors under seats or in bumpers can fail or become corroded
Low or flat airbag backup battery
SRS system has its own capacitor/battery — can trigger light when degraded
Previous deployment not fully reset
If airbags were deployed and the control module not replaced, light stays on permanently
Repairs you may need
Typical cost range: £80–£400 — Clock spring: £100–300. Sensor replacement: £80–200. SRS module reset after deployment: £150–400.
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