MOT advisory explained
“SRS warning lamp does not illuminate”
The airbag warning light should come on with the ignition and go out a few seconds later. The tester found that it never came on at all. That is not proof the airbags are fine. It is proof that the one thing designed to tell you about them has been silenced, sometimes by accident and sometimes on purpose.
SRS stands for supplementary restraint system: the airbags and seat belt pretensioners. Their warning lamp does a self-check every time you start the car. If it never lights, the tester cannot tell whether the system is healthy, and records that fact.
4.7% fail on the SRS lamp at the next test and 26.9% are advised again, one of the higher repeat rates for a lamp. A dead warning light is invisible in daily use, so it stays dead.
Some of these are deliberate. “taped over”, “tape covering lamp” and “blanked off” appear in the tester notes. A previous owner who taped over an airbag light did so because it was on, and it was on because something in the system had failed. If you bought the car used, that is the first thing to rule out.
A “supplementary restraint system warning lamp does not illuminate” advisory means the airbag warning light did not come on during its self-check with the ignition on, so the tester could not confirm the system’s status, and the car passes. Causes range from a blown bulb to a lamp covered to hide a fault. According to DVSA MOT data analysed by PriceMyRepair, 4.7% of 87,604 such advisories followed to the next test failed on the SRS warning lamp.
What the tester checked and why it matters
The self-check. Switch the ignition on and every warning lamp lights for a few seconds while the car tests its own systems. The airbag lamp should go out once the SRS module reports no faults. The MOT tester watches for this. A lamp that lights and goes out is a pass. A lamp that stays on is a failure, because the system has reported a fault. A lamp that never lights is this advisory.
Why a dead lamp is a problem. With no lamp there is no way to know whether the airbags will fire in a crash. A crash sensor, a seat belt pretensioner, a passenger seat occupancy sensor or the module itself could have failed months ago, and the only warning is the one that has been removed.
Honest and dishonest causes. Honest ones: a blown bulb on an older instrument cluster, a cluster fault, or a wiring break. Dishonest ones: the bulb removed, the lamp taped over, or a resistor plugged into an airbag connector to fool the module. “child seat fitted” appears in the notes too, and points to a passenger airbag switched off for a child seat on a car whose lamp shows that oddly.
Will it fail next year?
One wording, recorded 200,516 times, with 87,604 followed to the same vehicle’s next MOT.
| What happened at the next test | Share |
|---|---|
| Failed on the same component | 4.7% |
| Same advisory recorded again | 26.9% |
According to DVSA MOT data analysed by PriceMyRepair: 87,604 advisories followed to the same vehicle’s next test. Rows can overlap.
It sits with the other lamp advisories, near a dead high level brake light at 5.1% and a discoloured indicator at 6.1%. The failures are mostly lamps that have been reconnected and then, predictably, stayed on.
The repeat rate is what stands out. More than a quarter come back with the same note. A missing warning light does not remind anyone that it is missing.
| Advisory wording | Fails on same part | Advised again | Followed |
|---|---|---|---|
| Direction indicator slightly discoloured | 6.1% | 19.6% | 1,901,107 |
| Stop lamp(s) non-obligatory stop lamp not working | 5.1% | 26.3% | 526,670 |
| Headlamp has a product on the lens | 5.0% | 22.9% | 1,248,099 |
| Supplementary restraint system warning lamp does not illuminate | 4.7% | 26.9% | 87,604 |
| Position lamp slightly affected by the operation of another lamp | 3.9% | 12.7% | 121,142 |
| Seat belt webbing slightly damaged or frayed | 3.1% | 23.6% | 1,047,800 |
| Brake pedal wearing smooth | 1.4% | 26.2% | 320,684 |
Nothing to report on cars under seven years old. From 7–9 years the rate rises from 0.2 per 1,000 tests to 2.1 at 20 years and over. The failure rate goes the other way, from 5.7% down to 2.6% on the oldest cars, many of which have no SRS lamp to test because they predate the requirement.
| Age of car | Per 1,000 tests | Fails on same part | Followed |
|---|---|---|---|
| 7–9 years | 0.2 | 5.7% | 8,225 |
| 10–12 years | 0.5 | 5.3% | 17,338 |
| 13–15 years | 1.1 | 5.1% | 24,986 |
| 16–19 years | 1.8 | 4.5% | 23,011 |
| 20 years and over | 2.1 | 2.6% | 10,485 |
Any garage with a diagnostic tool can read the airbag module in minutes. If it reports no faults and the lamp is simply dead, it is a cluster or bulb problem. If it reports a stored fault, the lamp was hiding something, and that something is the repair.
On older cars the SRS lamp is a bulb in the instrument cluster and can be changed. On most cars built in the last fifteen years it is an LED soldered to the cluster board, and a dead one means a cluster repair or a wiring fault upstream.
If you find tape, a missing bulb or an unfamiliar plug behind the dashboard, assume the airbag system has a fault until a diagnostic scan says otherwise. Do not just restore the lamp and drive on.
Exact wording on your certificate
The advisory is for a lamp that does not light at all. The failure is for a lamp that lights and stays on, meaning the system has reported a fault.
| Line on the certificate | Result | Code |
|---|---|---|
| Supplementary restraint system warning lamp does not illuminate | Advisory — pass | 7.1.6 (a) |
| Supplementary restraint system warning lamp indicates a system malfunction | Major — fail | 7.1.6 (a) |
Nearly every entry has no position, because there is one lamp and it is on the dashboard. The tester notes are unusually sparse for this advisory, and the ones that exist are mostly about tape.
| Position written by the tester | Share of all instances |
|---|---|
| No position recorded | 98% |
| Front | 2% |
| Offside front | 0% |
| Nearside front | 0% |
| Central front | 0% |
| Central | 0% |
From 200,516 recorded instances. Testers can add their own note after the standard wording. The most common on this advisory: “air bag” (46), “airbag” (42), “taped over” (33), “srs / air bag” (29), “air bag light” (26), “child seat fitted” (10), “tape covering lamp” (4), “flickers” (4).
What it costs
| Job | Price fitted | Notes |
|---|---|---|
| Warning lamp bulb, older cluster, DIY | £10–£40 | Only where the lamp is a replaceable bulb |
A diagnostic scan is a short labour charge and is where to start. A cluster LED repair is a specialist job. If the scan finds an airbag fault, the cost depends entirely on the component: a seat belt pretensioner, a crash sensor, a clock spring in the steering wheel and an airbag module are all different bills. Ask for the fault code before any quote. Other prices are on the repair costs index.
Can I still drive with this advisory?
Treat it as an unknown. Until a scan confirms the system is fault-free, you do not know whether the airbags and pretensioners will do their job. Get the scan done soon, and sooner if you bought the car recently.
Enter your reg to see your car’s full MOT history, including whether this lamp has been noted before and whether the previous owner had it flagged.
Which cars get this advisory most?
The all-vehicle rate is 0.6 per 1,000 tests. On the models below it is three to nine times that.
| Model | Per 1,000 tests | Vs all cars | Tests |
|---|---|---|---|
| Citroen C5 | 5 | 9.2× | 226,154 |
| Peugeot 206 | 3 | 4.9× | 1,061,894 |
| Volkswagen Beetle | 3 | 4.5× | 586,588 |
| Peugeot 308 | 2 | 4.2× | 1,495,422 |
| Saab 9-3 | 2 | 4.0× | 589,429 |
| Peugeot Expert | 2 | 4.0× | 628,355 |
| Renault Kangoo | 2 | 3.7× | 700,467 |
| BMW 3 Series | 2 | 3.1× | 4,399,110 |
| Mitsubishi L200 | 2 | 3.0× | 935,407 |
| Citroen Dispatch | 2 | 3.0× | 556,497 |
Model families are grouped by the first word of the DVSA model name, so “Transit” covers every Transit variant. Only models with at least 60,000 tests are ranked.
The Citroen C5 leads at 9.2 times the average, twice the rate of the next model. The Peugeot 206, Peugeot 308 and the two vans that share their parts, the Peugeot Expert and Citroen Dispatch, put Peugeot and Citroen in five of the ten places. Instrument clusters and airbag wiring on those cars have known weak spots, and a lamp that fails honestly and one that is silenced deliberately look the same on the certificate.
The Volkswagen Beetle and Saab 9-3 are older designs with bulb-type clusters, where a blown bulb is the likeliest explanation.
What to do next
- Switch the ignition on and watch the cluster. Every lamp should light. If the airbag one is the only one missing, it is the lamp or something done to it.
- Look behind the dashboard trim for tape. It happens more than anyone would like. So does a missing bulb.
- Get the airbag module scanned. Ten minutes at any garage with a diagnostic tool. It is the only way to know whether the system is healthy.
- Fix what the scan finds, then the lamp. A restored lamp on a faulty system will simply stay on, and that is a failure.
SRS warning lamp advisory FAQ
What does supplementary restraint system warning lamp does not illuminate mean?
The airbag warning light did not come on during its self-check when the ignition was switched on. The tester therefore could not confirm the airbag system’s status. It is an advisory and the car passes.
Is a dead airbag light an MOT fail?
No. The failure is an airbag light that stays on, because that means the system has reported a fault. A light that never comes on is an advisory. According to DVSA MOT data analysed by PriceMyRepair, 4.7% of 87,604 such advisories failed on the SRS lamp at the next test.
Why would the airbag light not come on?
A blown bulb or cluster fault, a wiring break, or because a previous owner removed the bulb or taped over the lamp to hide an airbag fault. A diagnostic scan of the airbag module tells you which.
Are my airbags working if the light is off?
Nobody knows until the module is scanned. The light is the only indicator the car has. A dead light means no information, not good news.
How much does it cost to fix?
A diagnostic scan is a short labour charge. A bulb on an older cluster costs £10–£40. A cluster repair or an airbag component fault costs more and depends on the part. These are estimates and final quotes come from garages.
Which cars get this advisory most?
The Citroen C5, at 9.2 times the average rate, and other Peugeot and Citroen models including the Peugeot 206 and Peugeot 308.
How these figures were calculated. According to DVSA MOT data analysed by PriceMyRepair, from the DVSA anonymised MOT test results (Open Government Licence v3.0): 350,943,111 tests. This advisory was recorded 200,516 times; 87,604 of those were followed to the same vehicle’s next test between 180 and 730 days later. “Fails on the same part” means a failure at that next test under the same defect code and naming the same component, on either side of the vehicle. Testers do not always name a component the same way twice, so the figure is a floor. Method and how to cite.