Type a number plate to see a car’s MOT history in plain English: what each advisory and fault means, whether the mileage readings add up, and what to ask the seller if you are buying it. Below the checker, 20 common advisories and minor faults are explained one by one.

How to read an MOT result

Since 20 May 2018, the tester grades every fault:

• Dangerous: the car fails. DVSA says a dangerous vehicle should never be driven on the road, and that driving one is illegal, even if its previous MOT has not run out.
• Major: the car fails, and the fault must be repaired before it can pass.
• Minor: the car passes, but the fault should be repaired soon.
• Advisory: the car passes. DVSA describes advisories as a sign that a part will become defective soon, so keep an eye on them.

Before 20 May 2018, a fault was simply a fail. You may also see “PRS”, then and now: it means pass after rectification at station. The tester found a fail item, it was fixed at the test centre, and the car passed.

What the checker looks for

• Mileage readings that go down. This can be a typing mistake at the test or a replaced instrument panel, but it can also be a sign that the mileage has been wound back (“clocked”).
• Gaps of more than 15 months between MOTs. The car may have been off the road or abroad, or it may have been driven without an MOT.
• Advisories that come up at more than one MOT, which suggests they were never fixed.
• Dangerous faults found at any test, and safety recalls that have not been done. The manufacturer fixes a recall, and GOV.UK says you will not usually have to pay for it.

It also works out how many miles a year the car does, from the latest reading and the reading nearest to three years before it. For a car that has had only one or two MOTs, it uses the miles since the car was first used.

Common MOT advisories explained

Each heading below is the wording you are likely to see on the certificate, where the tester also says which part of the car it is, such as “Nearside Front”. Under it: what it means, whether it is safe, when it becomes a fail, and the usual fix. The fail rules come from DVSA’s MOT inspection manual for cars. This is general guidance, not a diagnosis of your car: if you are not sure, ask a garage to look at it.

• Tyres: worn close to the legal limit, cracking or perishing
• Brakes: discs worn, pitted or scored, pads wearing thin, pipes corroded, hoses deteriorated
• Suspension and steering: anti-roll bar links, suspension arm bushes, coil springs corroded, shock absorber misting, track rod ends, steering rack gaiters, wheel bearings, drive shaft boots
• Leaks, exhaust and rust: oil leaks, exhaust leaks, corrosion
• Glass, wipers and lights: windscreen damage, wiper blades, headlamp lenses

Tyres

“Tyre worn close to legal limit/worn on edge”

What it means: the tread is getting close to the legal minimum, or one edge of the tyre has worn faster than the rest.

Is it safe? It is legal for now, but a worn tyre grips less on wet roads. A tyre worn on one edge usually means the wheel alignment (the “tracking”) is out, so the new tyre will wear the same way unless that is put right.

When it fails: a car’s tyres need at least 1.6mm of tread in the main grooves across the central three-quarters of the tread, all the way round. Below that, the MOT fails with a dangerous fault, and driving on an illegal tyre can bring a fine of up to £2,500 and three penalty points per tyre.

The usual fix: replace the tyre, ideally before it reaches the limit, and have the alignment checked if one edge is worn.

“Tyre slightly damaged/cracking or perishing”

What it means: the rubber has fine cracks, usually on the sidewall or between the tread blocks, or small scuffs and nicks. Cracking comes with age and sunlight, so it is common on older tyres and cars that are not used much.

Is it safe? Fine surface cracks are not a danger in themselves. Deep cracks, a cut you can see the cords through, or a bulge on the sidewall are.

When it fails: a cut that reaches the ply or cords is a major fault if the cords can be seen, or if the cut is longer than 25mm (or 10% of the tyre’s width, if that is more) and the cords can be felt. A lump, bulge or tear caused by the tyre’s structure failing, lifting tread rubber, or exposed or damaged cords is a dangerous fault.

The usual fix: keep an eye on it, and replace the tyre if the cracks deepen. A tyre’s age is in the last four digits of the code on its sidewall: “3219” means week 32 of 2019.

Brakes

“Brake disc worn, pitted or scored, but not seriously weakened”

What it means: the brake discs (the metal discs that the pads grip) have worn thinner, have small pits from rust, or have grooves worn into them by the pads.

Is it safe? The brakes still work. Signs that the discs need replacing are a raised lip at the outer edge, deep grooves, or a judder through the pedal when you brake. Rust pitting is common on cars that stand unused for long periods.

When it fails: a disc that is significantly and obviously worn is a major fault, and one that is insecure, fractured or otherwise likely to fail is dangerous. Being worn below the maker’s limit is not a reason to fail on its own.

The usual fix: new discs on both sides of the axle, normally with new pads.

“Brake pad(s) wearing thin”

What it means: the friction material on the brake pads is getting thin.

Is it safe? Yes for now, but pads can wear quickly, especially in town driving. A squeal or grinding when you brake means they need checking straight away.

When it fails: a pad worn down to its wear indicator is a major fault, and below 1.5mm it is dangerous. The brake wear warning light on the dashboard is not a reason to fail by itself.

The usual fix: new pads on both sides of the axle, with the discs checked at the same time. Pads that are thin at one MOT often need replacing well before the next.

“Brake pipe slightly corroded” or “Brake pipe corroded, covered in grease or other material”

What it means: the metal pipes that carry brake fluid to each wheel have rust on them. “Covered in grease or other material” means the tester could not see the pipe well enough to judge it.

Is it safe? Light surface rust is common. Heavy rust weakens the pipe, and a pipe that bursts loses brake fluid, so the brakes stop working properly. Ask a garage how bad the corrosion is.

When it fails: a brake pipe that is damaged or excessively corroded is a major fault. A pipe at imminent risk of failing, or a leaking pipe, is dangerous.

The usual fix: replace the corroded pipes. Corrosion only gets worse, so a pipe that is advised year after year will fail in the end.

“Brake hose slightly deteriorated”

What it means: the rubber brake hoses, which join the metal pipes to the brakes at each wheel and flex as the wheels move, are showing their age, usually with fine surface cracks. The tester may instead record “Flexible brake hose slightly damaged, chafed or twisted”, which is a minor fault. Either way, the car passes.

Is it safe? A slightly worn hose is not an immediate danger. A hose that bulges when you press the brake pedal needs replacing, and a leaking hose is dangerous.

When it fails: a hose that is badly damaged, deteriorated, chafed, twisted or stretched (deep enough to show its reinforcement), bulges under pressure or is porous is a major fault. A hose likely to fail, or a leaking one, is dangerous.

The usual fix: replace the hose and bleed the air out of the brakes.

Suspension and steering

“Anti-roll bar linkage ball joint has slight play”

What it means: the anti-roll bar links the left and right suspension to stop the car leaning in corners. Short links with a ball joint at each end connect it to the suspension, and one of these joints has started to wear.

Is it safe? Slight play is not a safety problem in itself. Worn links usually knock or clunk over bumps.

When it fails: a suspension joint that is excessively worn is a major fault, and one likely to come apart is dangerous.

The usual fix: replace the link. It is one of the simpler suspension jobs.

“Suspension arm pin or bush worn but not resulting in excessive movement”

What it means: the rubber bushes or pins where a suspension arm is fixed to the car are worn or cracking, but the arm is not yet moving much.

Is it safe? Yes for now. As the wear grows, you may hear clunks, feel vague steering or a pull under braking, and see uneven tyre wear.

When it fails: a pin, bush or joint that is excessively worn is a major fault, and one likely to come loose is dangerous. Rubber bushes fail only when the rubber or its bonding is seriously deteriorated.

The usual fix: new bushes, or a new arm with the bushes already fitted, followed by a wheel alignment check.

“Coil spring corroded”

What it means: the road springs have rust on them.

Is it safe? A rusty spring is more likely to break, often near one end. A broken spring changes how the car sits and handles, so have it checked if the car leans or knocks.

When it fails: a spring that is broken or seriously weakened is a major fault, and so is a suspension part that is excessively corroded.

The usual fix: replace the springs on both sides of the axle, so the car stays level.

“Shock absorber has a light misting of oil”

What it means: a thin film of oil on the shock absorber, a sign that its seal has started to seep. Certificates since 2018 word it “Shock absorbers has light misting of oil”.

Is it safe? Yes. The MOT manual says slight seepage is not a reason to fail. Worn shock absorbers make the car bounce after bumps and dive under braking.

When it fails: a shock absorber that is leaking badly, damaged so it does not work, or giving almost no damping is a major fault, and so is an excessively worn shock absorber bush. A slightly worn bush is only an advisory.

The usual fix: nothing yet. If it gets worse, replace the shock absorbers on both sides of the axle.

“Track rod end ball joint has slight play”

What it means: the track rods connect the steering to the front wheels, with a ball joint at the outer end. That joint has started to wear.

Is it safe? Slight play is a warning, but steering joints are safety-critical, so do not leave it for long. Wear makes the steering feel vague.

When it fails: a steering ball joint with excessive wear or free play is a major fault, and one at serious risk of coming apart is dangerous.

The usual fix: replace the track rod end, then have the wheel alignment set.

“Steering rack gaiter damaged or deteriorated, but preventing the ingress of dirt”

What it means: one of the rubber covers that keep dirt and water out of the steering rack is cracked or worn, but still keeps the dirt out. The same wording is used for the dust cover on a steering ball joint, such as “Track rod end ball joint dust cover damaged or deteriorated, but preventing the ingress of dirt”. This is a minor fault, so the car passes.

Is it safe? Yes for now, but dirt and water getting in will wear out the joint or the steering rack.

When it fails: a cover that is missing, or no longer keeps the dirt out, is a major fault.

The usual fix: replace the gaiter or cover. It is far cheaper than the parts it protects.

“Wheel bearing has slight play”

What it means: the bearing that the wheel turns on has a little movement in it.

Is it safe? Yes for now. A worn wheel bearing usually rumbles or hums, louder with speed and often when turning one way.

When it fails: a bearing with excessive play, or one that is excessively rough, is a major fault. One so worn it could break up is dangerous.

The usual fix: replace the bearing, or the hub with the bearing in it, when the noise starts or the play grows.

“Drive shaft joint constant velocity boot severely deteriorated”

What it means: the rubber boot over a constant velocity (CV) joint, one of the flexible joints on the shafts that drive the wheels, is cracked. The boot keeps the joint’s grease in and dirt out. This is a minor fault, so the car passes.

Is it safe? Yes for now, but once the boot splits, grease escapes and grit gets in, and the joint wears out. A worn outer joint usually clicks when you drive with the steering on full lock; a worn inner joint more often causes vibration or a clunk as you pull away.

When it fails: a boot that is missing, split or loose, so it no longer keeps dirt out, is a major fault.

The usual fix: replace the boot before the joint is damaged. If the joint is already worn, the joint or the whole drive shaft needs replacing.

Leaks, exhaust and rust

“Oil leak, but not excessive”

What it means: the tester saw oil leaking, but not enough to fail.

Is it safe? Usually, but check the oil level regularly, because running low can damage the engine. Oil dripping onto a hot exhaust can also smoke.

When it fails: with the engine idling, a leak that makes a pool more than 75mm across within five minutes is a major fault, and a continuous leak that is a serious risk to road safety is dangerous. Leaks of coolant, screen wash and AdBlue (the fluid some diesel cars use to cut their emissions) are not reasons to fail.

The usual fix: a garage can find where it is coming from, often a gasket or seal.

“Exhaust has a minor leak of exhaust gases”

What it means: exhaust gas is escaping from a joint or a rusty section before it reaches the tailpipe.

Is it safe? A small leak at the back of the car is mainly noise. Exhaust gas contains carbon monoxide, though, so if you can smell fumes inside the car, get it fixed straight away.

When it fails: a major leak, an insecure exhaust, fumes getting into the car, or a leak that could affect the emissions test are major faults. Fumes that are a danger to the people inside are dangerous.

The usual fix: a new gasket, clamp or section of exhaust.

“Corroded but not seriously weakened”

What it means: the tester found rust on a part of the suspension, most often the sub-frame or a suspension arm, but not enough to weaken it. The wording names the part, as in “Rear sub-frame corroded but not seriously weakened”. Rust on the body itself has its own wording: “Integral body structure is corroded but structural rigidity is not significantly reduced”.

Is it safe? Yes for now. Surface rust is common on older cars; the risk is that it spreads and weakens the metal.

When it fails: a suspension part that is excessively corroded is a major fault, and one that is fractured or likely to fail is dangerous. For the body, rust that significantly reduces the strength of the structure is a major fault, and rust likely to affect the steering or brakes is dangerous. The metal within 30cm of the mountings for the sub-frame, springs and suspension parts fails if rust there significantly weakens it.

The usual fix: clean off the rust and treat and protect the metal early. Badly rusted metal needs welding or new parts; a sub-frame can be replaced.

Glass, wipers and lights

“Windscreen damaged but not adversely affecting driver’s view”

What it means: a chip or crack that does not block the driver’s view. This is a minor fault, so the car passes.

Is it safe? Yes for now, but chips can spread into cracks with changes in temperature and bumps in the road.

When it fails: damage larger than 10mm across in the area directly in front of the driver (a 290mm-wide strip of the wiped area, centred on the steering wheel), or larger than 40mm elsewhere in the wiped area, is a major fault.

The usual fix: a small chip can often be repaired if it is done early. Check whether your car insurance covers windscreen repairs.

“Wiper blade defective”

What it means: the rubber on a wiper blade is split, worn or hardened, so it smears. This is a minor fault, so the car passes.

Is it safe? It makes it harder to see in the rain, so change it soon.

When it fails: a missing blade, or one that obviously does not clear the windscreen, is a major fault.

The usual fix: new wiper blades, which you can fit yourself in a few minutes.

“Headlamp lens slightly defective”

What it means: a headlamp lens is cloudy, yellowed, crazed or slightly damaged. The same rules apply to the reflector inside the lamp. This is a minor fault, so the car passes.

Is it safe? A cloudy lens puts less light on the road and scatters more glare at other drivers.

When it fails: a lens or reflector that is seriously defective or missing is a major fault, and so is a headlamp aimed outside the limits.

The usual fix: a lens restoration kit often clears cloudy plastic lenses. A damaged headlamp needs replacing, and a garage can adjust the aim.

Questions people ask

What does an advisory on an MOT mean?

The car passed, but the tester saw something that is wearing and will need attention in future. It is not a fault yet. If the same advisory comes up at the next MOT, it has probably got worse.

Can I drive my car with an MOT advisory?

Yes. Advisories and minor faults do not stop the car passing. A dangerous fault is different: DVSA says the car should not be driven until it has been repaired.

How do I check a car’s MOT history?

Type its number plate into the checker above. It shows every MOT the DVSA holds for the car, with each advisory and fault explained, and checks the mileage readings. You do not need the V5C logbook.

Thinking of switching to electric? The electric car cost calculator uses the same MOT mileage readings to show what an electric car would cost you. To work out the cost of a trip, use the journey cost calculator.

Sources

DVSA: MOT inspection manual for cars and passenger vehicles (sections 1, brakes; 2, steering; 3, visibility; 4, lamps; 5, axles, wheels, tyres and suspension; 6, body and structure; 8, nuisance); DVSA: how the new MOT defect categories will work; GOV.UK: check if a vehicle has been recalled; Torbay Council: tyre penalties; DVSA: MOT history API.

MOT histories contain public sector information licensed under the Open Government Licence v3.0.