Does an airbag light fail an MOT?

Yes. An SRS malfunction indicator lamp indicating a system malfunction is a major defect under section 7.1.6 of the inspection manual, and 84,147 MOT failures were recorded against it in the DVSA data behind this site. There is an important difference from the ABS lamp, though: a missing or non-illuminating airbag lamp is not a failure, because a lamp that cannot light cannot indicate a fault. Removing the bulb is not a loophole worth using — it hides a system you would want to know about — but it is not what the test catches.

Will my airbags still work with the airbag light on?

Assume not. When the restraint module detects a fault it normally disables deployment across the whole system rather than the single circuit that failed, because it can no longer be confident about what it would be firing. That includes the seat belt pretensioners, which tighten the belts in the first milliseconds of an impact. Wear your belt, and treat the car as an older one without airbags until it has been fixed.

Why did my airbag light come on after moving the seat?

Because the wiring for the side airbag, the pretensioner and the seat occupancy sensor runs under the seat and plugs in through a connector there, and sliding the seat to the end of its runners can stretch, chafe or unseat it. It is the single most common cause of this lamp, and the connectors are always yellow so they are easy to identify. Sometimes it is genuinely just a plug that needs reseating — but the stored code still has to be cleared with a scan tool afterwards.

Can I reset the airbag light myself?

Only with a scan tool that talks to the restraint module, and only after the fault is fixed. Disconnecting the battery does not clear SRS codes on most cars, and generic engine code readers cannot see them. Clearing the code without repairing the fault simply lights the lamp again at the next ignition cycle, and if it does not, you have a disabled system with no warning at all — which is considerably worse than the lamp.

Should I worry about an airbag light on a used car I'm viewing?

Yes, more than most warning lamps. It can be a connector under a seat, which is minor. It can also mean the car has been in a collision and the restraint system has been reset or rebuilt with parts that do not report correctly, which tells you something about the repair that the seller may not have. Check the MOT history for previous SRS failures, look for mismatched trim or paint, and have the module scanned before committing.

Dashboard warning light

Airbag warning light

Last updated 27 July 2026

Quick answer

The supplementary restraint system has found a fault and has almost certainly disabled itself. The car drives exactly as normal, which is what makes this lamp so easy to ignore — but you should assume the airbags and seat belt pretensioners will not fire in a crash while it is lit.

What to do: Get it checked within days
Can you drive?: Briefly, gently

Why it is red

Reserved for hazards and for faults where continuing could injure somebody or destroy something expensive. Most red lamps mean stop, though a few mean the opposite, so read the lamp rather than the colour.

What turns it on

The restraint control module checks the resistance of every deployment circuit each time the ignition is switched on, and monitors them continuously afterwards: driver and passenger airbags, side and curtain airbags, seat belt pretensioners, crash sensors and the occupancy sensor in the passenger seat. Any circuit reading outside tolerance stores a code, lights the lamp and puts the system into a safe state where it will not deploy.

What to do about it

Treat the car as having no airbags until it is fixed, and make sure everyone is wearing a seat belt. The belt is doing all the work now.
Think about what happened just before the lamp appeared. Seats slid all the way forward or back, a valet, footwell work, a flat battery or a jump start are the classic triggers, and they point at a connector rather than a component.
Check under both front seats for a yellow connector that has been knocked loose. Restraint wiring is always yellow, and the under-seat plugs are the single most common cause of this lamp.
Get it scanned with equipment that reads the restraint module. A basic engine code reader will not see airbag codes — it needs to talk to the SRS module specifically.
Do not work on the system yourself with the battery connected. Airbag modules hold enough stored charge to deploy after the battery is disconnected, and manufacturers specify a waiting period before anything is unplugged.
Book the repair before the MOT. This is a major defect and there is no advisory version of it.

Can you keep driving?

Briefly, gently

Mechanically the car is unaffected and it will not break down. The reason this is not simply a 'yes' is that you have quietly lost the protection you would only find out about at the worst possible moment, and in a serious impact that difference is measured in injuries. There is also a smaller risk in the other direction: some faults can cause an unwanted deployment. Get it read within days rather than living with it, and keep passengers out of the front seat if the fault is on the passenger side.

What causes it

A loose or corroded connector under a front seat, disturbed by the seat being slid on its runners
A failed clock spring in the steering column, the coiled ribbon that keeps the driver's airbag connected as the wheel turns — often accompanied by a horn or steering wheel controls that have stopped working
A faulty passenger seat occupancy mat, which is a known weak point on a lot of cars
A seat belt pretensioner that has been triggered, or has a failed circuit
Corroded crash sensor wiring, particularly in the sills and footwells of cars that have taken water
A previously deployed system that has been reset rather than properly repaired, which is a serious concern on a used car
Low battery voltage or a jump start, which can log a fault the module then latches

Does it fail an MOT?

Yes. A tester records it as a major defect, under the wording An SRS malfunction indicator lamp (MIL) indicates a system malfunction in the MOT inspection manual (section 7.1.6).

Airbags and restraint systems fitted as original equipment, other than on Class 3 vehicles. The lamp is only failed when it is indicating a malfunction: unlike the ABS lamp, one that never lights at all is not a failure, because a lamp that cannot light cannot report a fault. A warning message on a dashboard display is not a defect on its own, though a tester may use it to confirm what the lamp means.

It is not a technicality either. Across the DVSA test data behind this site, 84,147 MOTs were failed on it, spread across 404 different models.

Models where it happens most

Share of all tests on that model where this defect was recorded, among models with at least 20,000 tests. Compared against 0.61% across every model that records it.

Nissan NV2002.47%
609 of 24,703 tests
Mercedes-Benz CLK1.91%
479 of 25,027 tests
Renault Kangoo1.68%
878 of 52,135 tests
Volkswagen Beetle1.47%
596 of 40,523 tests
MG 31.44%
360 of 24,958 tests
Nissan Note1.30%
1,907 of 146,828 tests
BMW Z41.27%
448 of 35,178 tests
Peugeot 2061.26%
434 of 34,316 tests

A high rate is not proof a model is badly built. Fleet age, annual mileage and how a model is used all move these figures, and vans and commercial derivatives sit near the top of most emissions defects for that reason rather than through poor engineering.

Fault codes that turn this light on

The lamp tells you which system reported a problem. The code stored behind it names the check that failed, which is the difference between knowing something is wrong and knowing where to look. These are the ones that commonly sit behind this symbol.

B0001 Driver's airbag circuit fault
B0010 Passenger's airbag circuit fault
B0020 Left side airbag circuit fault
U0151Lost Communication with Restraints Control Module

Got a different code? Look it up — the index covers every standard OBD-II code.

Common questions

Does an airbag light fail an MOT?: Yes. An SRS malfunction indicator lamp indicating a system malfunction is a major defect under section 7.1.6 of the inspection manual, and 84,147 MOT failures were recorded against it in the DVSA data behind this site. There is an important difference from the ABS lamp, though: a missing or non-illuminating airbag lamp is not a failure, because a lamp that cannot light cannot indicate a fault. Removing the bulb is not a loophole worth using — it hides a system you would want to know about — but it is not what the test catches.
Will my airbags still work with the airbag light on?: Assume not. When the restraint module detects a fault it normally disables deployment across the whole system rather than the single circuit that failed, because it can no longer be confident about what it would be firing. That includes the seat belt pretensioners, which tighten the belts in the first milliseconds of an impact. Wear your belt, and treat the car as an older one without airbags until it has been fixed.
Why did my airbag light come on after moving the seat?: Because the wiring for the side airbag, the pretensioner and the seat occupancy sensor runs under the seat and plugs in through a connector there, and sliding the seat to the end of its runners can stretch, chafe or unseat it. It is the single most common cause of this lamp, and the connectors are always yellow so they are easy to identify. Sometimes it is genuinely just a plug that needs reseating — but the stored code still has to be cleared with a scan tool afterwards.
Can I reset the airbag light myself?: Only with a scan tool that talks to the restraint module, and only after the fault is fixed. Disconnecting the battery does not clear SRS codes on most cars, and generic engine code readers cannot see them. Clearing the code without repairing the fault simply lights the lamp again at the next ignition cycle, and if it does not, you have a disabled system with no warning at all — which is considerably worse than the lamp.
Should I worry about an airbag light on a used car I'm viewing?: Yes, more than most warning lamps. It can be a connector under a seat, which is minor. It can also mean the car has been in a collision and the restraint system has been reset or rebuilt with parts that do not report correctly, which tells you something about the repair that the seller may not have. Check the MOT history for previous SRS failures, look for mismatched trim or paint, and have the module scanned before committing.

This is general guidance, not a diagnosis. Manufacturers draw the same system differently and reuse symbols for more than one function, so check the handbook for your own car before acting on anything here.

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