Quick answer
If the airbag light stays on after startup, flashes unexpectedly or indicates a system fault, the vehicle may fail its MOT.
The warning light is there to show possible faults in the airbag or seatbelt pretensioner system.
Why the airbag light can fail MOT
Safety system fault
Airbags may not deploy correctly in a collision.
Pretensioner issue
Seatbelt restraint components may also be affected.
Stored fault code
The control module has detected a problem.
Electrical fault
Wiring, connectors or battery voltage issues.
Crash history
Previous accident damage may trigger faults.
Removed components
Seats or steering wheels changed incorrectly.
Common reasons the airbag light comes on
- 1Loose connector under front seats
- 2Low battery voltage or weak battery
- 3Clock spring fault in steering wheel
- 4Seat occupancy sensor problem
- 5Crash sensor or module fault
How to fix it before MOT
The fault usually needs diagnosing with scan equipment. Clearing the light without repairing the issue often means it will return.
Because airbags are safety-critical, repairs should be done properly using suitable parts and procedures.
Related warning light and MOT guides
Frequently asked questions
If the light comes on then goes off?
That is usually normal during startup self-check.
Can a weak battery trigger it?
Yes, low voltage can sometimes cause faults.
Can I clear it myself?
You may clear codes, but faults often return if unresolved.
Is it safe to ignore?
No, the restraint system may not work properly.
Will it always fail MOT?
An active warning light commonly causes failure.
Best next step?
Get the system diagnosed before the test.