The SRS warning light stayed on with the engine running, meaning the airbag system has logged a fault and may not deploy correctly. It's a testable item on cars fitted with airbags.
An airbag warning light is an automatic MOT failure on any car first used from 1 September 2009. It is a major defect, so the car cannot pass with it lit. Common causes are a seat belt pretensioner, a crushed wiring loom under a seat, or a clock spring — typically £90 to £350 to fix.
Answered by Bob — 32 years on the tools, DVSA-approved MOT centre, Birnam, Perthshire.
Wording as it commonly appears on an MOT certificate: “Airbag warning lamp indicates a fault”.
What does it mean?
The SRS warning light stayed on with the engine running, meaning the airbag system has logged a fault and may not deploy correctly. It's a testable item on cars fitted with airbags.
How serious is it?
Usually recorded as: Major. The tester assesses the actual vehicle on the day, so your certificate is what counts.
What normally causes it?
- A broken wire or corroded connector under a front seat — the usual suspect, because the loom flexes every time the seat is moved
- A failed clock spring in the steering column, which also often kills the horn and wheel controls
- A seat occupancy or belt pretensioner sensor fault
- A previously deployed airbag never properly reset
What a mechanic would check
Read the SRS system with equipment that can actually talk to it — a basic code reader often can't. Then check the obvious mechanical suspects first: the connectors under the seats and the clock spring. Never start pulling airbag connectors about without disconnecting the battery and letting the system discharge.
What might need replacing
- A connector or wiring repair under the seat
- A clock spring
- A sensor or, less often, an SRS module
Can you still drive it?
It's a failure. Mechanically the car may be fine, but with the light on you cannot assume the airbags will work in a crash — and that's the whole point of them.
Repair cost
A dirty connector under a seat is a cheap fix; a clock spring or module is a bigger job. Get the system read properly before anybody quotes you.
Before the retest
Pull each belt all the way out and check the webbing for cuts, fraying and stitching damage, then give it a sharp tug to make sure it locks. Every buckle should latch and release cleanly. If an airbag or seat belt warning light is on, have the fault read and fixed before the retest; a lit warning lamp is a fail in its own right.
Retest rules
If the vehicle stays at the test centre for repair and is retested within 10 working days, a partial retest is often free; some items qualify for a free retest if you bring the car back by the end of the next working day. The exact conditions are set out on GOV.UK, so confirm with the test centre before you leave. A major or dangerous failure means the car cannot legally be driven away unless the previous MOT is still valid and nothing dangerous was recorded — check your certificate first.
Related help
More seat belts and restraints failures · MOT failure decoder · Ask a mechanic about your certificate
This is general guidance from a UK mechanic, not a substitute for a physical inspection. Only the tester who inspected your vehicle can confirm what was recorded and why.