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What does my MOT advisory mean?
Paste the wording from your certificate. We’ll translate it, price the repair at an independent garage, and tell you how often it turns into a failure.
Independent garage pricesDVSA test data16 advisories decoded
An MOT advisory is a note from the tester about wear that has not yet reached the failure threshold — your car passed and nothing obliges you to act. Across 145 million advisories tracked from one test to the next, the median gap between an advisory and the failure it predicts is 376 to 379 days.
How often does an advisory become a failure?
No garage can tell you this. We measured it from the DVSA test record — every advisory followed forward to the same vehicle’s later tests, across nine defect categories.
Calculated from the DVSA MOT testing bulk dataset (Open Government Licence v3.0): 145,103,213 advisories tracked across 216,057,619 pairs of consecutive tests. “Becomes a failure” means the same defect category was recorded as a major or dangerous item at a later test. Brake fluid is not shown separately — it sits in the brake category, and a figure about wearing components does not describe a fluid that absorbs moisture on a calendar.
376
days, median, between an advisory and the failure it predicts — one MOT cycle almost exactly
37%
of suspension advisories are still there a year later, unfixed — the least acted-on group we measured
1 in 5
suspension advisories comes back as a failure, twice the rate of brakes or tyres
Suspension is the one to act on. Nearly one in five comes back as a failure, and it also has the lowest fix rate of anything we measured. That combination is not a coincidence. Worn brake pads squeal and a worn tyre is visible on the drive; a corroded spring or a perished arm bush makes no sound and lights no lamp, so it gets postponed until the tester insists.
An oil leak advisory almost never fails. 1.3%, the lowest figure we have, and the highest ignore rate at 43.5%. Drivers who leave it are behaving rationally as far as the test is concerned, and it would be dishonest of us to pretend otherwise. Whether it is rational for the engine is a different question, and one for your garage rather than the MOT.
The gap is always a year. Whatever the category, the median time between an advisory and the failure it predicts is 376 to 379 days. That is not a fact about how parts wear. It is a fact about people: drivers do not book the repair when they read the advisory, they wait for the next test to force it.
How the odds change with the age of your car
The same advisory does not carry the same risk on a five-year-old car and a fifteen-year-old one. Pick an age.
Same dataset, broken down by vehicle age at the time of the advisory. Shown for the five categories where the breakdown has been calculated. Suspension peaks at fifteen years — the highest figure anywhere in the record, for any group at any age. Beyond twenty years most curves fall again, which reflects which cars are still on the road rather than any improvement in the parts.
Every advisory we decode
The sixteen phrases that come up most often on UK certificates. Prices are fitted at an independent garage.
| Advisory phrase | What it means | Cost to fix | Urgency |
|---|---|---|---|
| Brake pads wearing thin | Pads have life left, but not much | £90–£220 | Soon |
| Brake disc worn, pitted or scored | Disc surface deteriorating | £180–£460 | Soon |
| Brake fluid contaminated | Fluid has absorbed water | £50–£90 | Soon |
| Tyre worn close to legal limit | Tread near 1.6mm | £60–£120 each | Now |
| Tyre worn on inner or outer edge | Alignment or suspension fault | £100–£200 | Soon |
| Coil spring corroded | Spring steel pitting with rust | £130–£320 | Soon |
| Shock absorber has light misting of oil | Damper seal starting to weep | £150–£360 | Watch |
| Anti-roll bar linkage has slight play | Drop link joint wearing | £40–£90 | Watch |
| Suspension arm pin or bush worn | Rubber bush perishing in an arm | £140–£280 | Soon |
| Ball joint dust cover damaged | Boot split, joint exposed to water | £70–£160 | Soon |
| Wheel bearing has slight play | Bearing starting to wear | £120–£300 | Soon |
| Exhaust has a minor leak | Small blow in a joint or section | £60–£300 | Soon |
| Oil leak, but not excessive | Seepage without dripping | £150–£800 | Watch |
| Corrosion within 30cm of a mounting | Rust near a structural point | Inspect first | Now |
| Headlamp aim too high or low | Beam pointing wrong | £20–£40 | Soon |
| Number plate lamp not working | Bulb out | £10–£25 | Watch |
Independent garage prices, parts and labour. Main dealers typically charge around 50% more. These are estimates — final quotes come from garages.
How these figures were calculated
Every number on this page comes from the same place, and we would rather show the working than ask you to take it on trust.
Our source is the DVSA anonymised MOT testing dataset, published under the Open Government Licence v3.0. We processed 829.7 million test records and matched them into 216,057,619 pairs of consecutive tests on the same vehicle, then tracked 145,103,213 advisories forward to see what happened at the later test.
| Term | How we define it |
|---|---|
| Became a failure | The same defect category was recorded as a major or dangerous defect at a later test on the same vehicle. |
| Ignored | The same advisory was recorded again at a later test, with no evidence of it having been resolved. |
| Fixed | The advisory did not appear again and did not become a failure. |
| Median gap | The median number of days between an advisory and the failure that followed it. |
| By vehicle age | The same calculation, split by how old the car was on the day the advisory was written. |
Two limits worth stating plainly. Figures are grouped by DVSA defect category, not by individual component — code 5.3 covers the whole suspension rather than springs alone, so a category figure is an upper bound for any single part within it. And eight of the nine categories have been calculated so far, which is why superlatives on this page are stated against the categories we have measured rather than against the whole record.
Free to reference and cite
This analysis is free for journalists, researchers and other publications to use. If you use the figures, please credit PriceMyRepair and link back to this page. The charts are free to reproduce on the same terms.
Need the underlying tables, a breakdown we haven’t published, or a comment for a piece you’re writing? Email info@pricemyrepair.co.uk and we’ll reply the same day.
What an MOT advisory actually is
An advisory is a note from the tester saying something is wearing out but has not yet reached the point of failure. Your car passed. Nothing on the certificate obliges you to act — but the tester wrote it down because, in their judgement, it will need attention before long.
The wording is the problem. Advisories are written in the language of the inspection manual, not the language of a garage invoice, so “suspension arm pin or bush excessively worn” tells you nothing about whether you are facing £60 or £600. That gap is what this tool closes.
Advisories are also the most useful thing on the certificate for planning. A pass with three advisories is a car telling you what next year’s bill looks like, and every one of them is cheaper dealt with now than after it has failed and taken something else with it.
Advisory, minor, major: what is the difference?
Advisory is a note, not a defect. Your car passed and there is no obligation attached — the tester is flagging wear that will need attention eventually.
Minor is a defect that does not affect safety and does not fail the test. It appears on the certificate as a minor defect and should be repaired as soon as possible, but you drive away with a pass.
Major fails the test. So does dangerous, which additionally means the car should not be driven at all until it is fixed. The line between an advisory and a major is often just a measurement — a tyre at 2mm is an advisory, at 1.5mm it is a fail.
The advisory that keeps coming back
One advisory is information. The same advisory three years running is a countdown. If “suspension arm pin or bush deteriorated” appeared on the nearside front in each of the last three tests, that bush has not stabilised — it has been getting worse while nobody looked, and the tester has been telling you so.
Repeating advisories are also the cheapest to act on, because they are the ones you have had the most warning about. The bush flagged three times is still a bush; left until it fails, it is a bush plus whatever it damaged on the way — a tyre worn on one edge, a ball joint that took the extra movement, or a fail and a retest fee.
How the decoder works
It matches your text against a dictionary of the phrases DVSA testers actually use. No guessing and no AI — if we recognise the wording you get the answer we would give you ourselves, and if we do not, we say so rather than inventing something.
Testers write in a fairly fixed vocabulary because the inspection manual gives them the words, which is why matching works. What varies is the position — nearside, offside, front, rear — and that does not change what the part is or what it costs, only which corner of the car it is on.
Prices come from the same tables as the rest of this site: independent garage rates, parts and labour, for the specific job. Where a repair varies a lot by car — an exhaust section on a supermini versus a full system on a diesel estate — we give the range rather than pretending to a precision we do not have.
MOT advisory FAQ
Do I have to fix an MOT advisory?
No. An advisory is a note, not a requirement — your car passed and you can legally drive away without touching it. But the tester wrote it because something is wearing out, and every advisory is cheaper to deal with before it becomes a failure.
Will an advisory fail my next MOT?
It might. The gap between an advisory and a failure is often just a measurement — a tyre at 2mm is an advisory, at 1.5mm it’s a fail. Wear doesn’t reverse, so an advisory this year is a strong candidate for a failure next year unless you act.
What does “nearside” and “offside” mean on an MOT?
Nearside is the passenger side of the car — the side nearest the kerb. Offside is the driver’s side. Testers use these instead of left and right because they don’t change meaning depending on which way you’re facing the car.
Can I sell a car with MOT advisories?
Yes, and they’re public — anyone can look up the MOT history from the registration, so a buyer will see them whether you mention them or not. Being upfront tends to work better than being found out, and fixing the cheap ones first is usually worth more than the repair costs.
What does “corrosion but not excessive” mean?
Rust the tester has judged not yet serious enough to fail. It matters where it is: surface rust on a bracket is one thing, corrosion within 30cm of a suspension mounting or seatbelt anchorage is another, because that’s structural and only gets worse.
Is a shock absorber “misting” a problem?
Not yet. Misting means a fine film of oil on the damper body — the seal is starting to weep but hasn’t given up. It becomes a failure when it’s “leaking”, so misting is your warning to budget for a pair rather than a reason to book immediately.
How long do MOT advisories stay on record?
Permanently. Every advisory from every test since the records went digital is available on the government’s MOT history service and stays there — which is why a repeating advisory is so visible to a buyer, and why clearing one is worth doing properly.
Should I check MOT advisories before buying a used car?
Always. The MOT history is the most honest document about a used car you can get for free — it shows what’s been flagged, what was fixed, and what’s been quietly ignored for three years. A car with the same advisory repeating is a car with a bill attached.
Which MOT advisories are most likely to become a failure?
Suspension, by a clear margin — 18.7% of suspension advisories became a failure at a later test, against 9.9% for tyres and 9.4% for brake parts. Steering follows at 15.2% and lamps at 14.4%. At the other end, an oil leak advisory becomes a failure just 1.3% of the time. Across every category the median gap is around 376 days, which is simply the next MOT.