The most common MOT failures are lights and electrics, suspension, brakes and tyres. Most are cheap to put right: a bulb or a wiper blade costs a few pounds. The expensive ones are suspension parts, brakes when the discs need replacing, exhaust and emissions faults, and corrosion to the structure of the car.
Knowing what fails, and what it costs, helps you price a car and read its MOT history for signs of a car that has been looked after or one kept going as cheaply as possible.
How often cars fail, and on what
In DVSA MOT data for 2023, covering 32.7 million tests on cars and light vans, 71% passed first time. The table shows the share of all tests that found at least one failure in each area. A single test can fail in more than one area, so the figures do not add up to the 29% that failed.
| Area | Share of tests with a failure |
|---|---|
| Lights and electrics | 11.3% |
| Suspension | 9.0% |
| Brakes | 6.8% |
| Tyres | 6.4% |
| Visibility (wipers, windscreen, mirrors) | 4.8% |
| Body and structure | 3.5% |
| Exhaust and emissions | 3.1% |
| Steering | 1.8% |
These are national figures across every make and model. Our MOT reliability pages show how individual models compare.
The cheap fixes
Lights and electrics
Blown bulbs are the single biggest cause of failure. A bulb usually costs a few pounds, and roughly £10 to £30 fitted at a garage, more where the bumper or headlamp has to come off to reach it. A failed LED unit is different: on some cars the whole lamp is replaced, which can run to hundreds of pounds.
Visibility
Split or smeared wiper blades, empty washers and windscreen damage fall here. Wiper blades cost roughly £10 to £30 a pair. A chip in the driver's line of sight wider than 10mm fails the test, as does damage over 40mm anywhere else in the area the wipers sweep. A chip repair is cheap and is often covered by insurance; a new windscreen can cost several hundred pounds, more if the car has cameras behind the glass that need recalibrating.
Tyres
A tyre fails if the tread is below 1.6mm across the central three quarters of its width, or if it has cuts, bulges or exposed cords. A mid-range tyre for a typical family car costs roughly £60 to £150 fitted, more for larger wheels and performance sizes.
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The more expensive fixes
Suspension
Broken coil springs, worn bushes, ball joints and anti-roll bar drop links are common, especially on cars driven over potholes. A drop link is often roughly £50 to £150 fitted. A coil spring or a wishbone is more like £100 to £300 each. Springs and shock absorbers are often replaced in pairs across an axle, which doubles the bill.
Brakes
Worn pads, scored or corroded discs, seized calipers and corroded brake pipes all fail. Pads alone are roughly £100 to £200 an axle; discs and pads together are more like £150 to £350. A seized caliper or a set of corroded brake pipes can add a few hundred pounds more.
Exhaust and emissions
A blowing exhaust, a missing or damaged catalytic converter, or a car that fails the emissions test can be expensive to diagnose and fix. A rear silencer is often a few hundred pounds at most. A catalytic converter or a diesel particulate filter can cost well over that, and an emissions failure sometimes means an engine fault rather than an exhaust one.
Body, structure and steering
Corrosion to sills, floor pans and suspension mounting points fails the test when it weakens the structure. The cost depends entirely on the extent: a small patch weld may be affordable, while widespread rot can cost more than an older car is worth. Steering failures are less common. A worn track rod end is usually roughly £50 to £150; a steering rack is considerably more.
All of these figures are approximate. Prices vary by car, by garage and by region, so get a quote for the specific job.
How failures appear in an MOT history
Every test result since 2005 is held by the DVSA. Our free MOT check shows each test with its result, the defects recorded and the mileage. A failed test is usually followed by a pass a few days later, once the work is done. A defect fixed at the test station straight after the test is shown as a pass after rectification rather than a fail. Our guide to MOT defect categories explains how dangerous, major and minor defects are recorded.
When you read a history, look for:
- The same item failing again and again. Repeated failures on the same corner of the suspension or the same brake point to a cheap repair each time rather than a proper one.
- Corrosion failures. Structural rot rarely gets better, and a weld repair one year can be followed by another the next.
- Failures that were advisories the year before. This is normal, but it shows how the car has been maintained. Our guide to MOT advisories explains which ones to take seriously.
- A test that failed with no pass afterwards. If the car was then sold, the work may never have been done.
What to do with what you find
A failure followed by a pass is a record that the work was done, not a reason to walk away. Use what you find to ask the seller for invoices and to set your price. If the current MOT has advisories for items on this list, budget for them at the next test.
The MOT record does not cover finance, write-offs or theft. The £9.99 full history check adds those before you hand over any money.
Common questions
What is the most common reason a car fails its MOT?
Lights and electrics. In DVSA MOT data for 2023, 11.3% of tests on cars and light vans found at least one failure in that area, more than any other. Most are blown bulbs, which are among the cheapest faults to fix.
How many cars pass their MOT first time?
In DVSA MOT data for 2023, 71% of tests on cars and light vans were a pass first time. The rest needed at least one repair before the car could pass.
Is a car with a long list of past MOT failures a bad buy?
Not necessarily. Most cars fail at some point, and a failure that was fixed and passed the same week shows the work was done. Look for the same item failing year after year, or failures for corrosion, which suggest a car that has been patched rather than repaired.
Can I check a car's MOT failures before I view it?
Yes. The MOT history for any car tested in Great Britain is public. Enter the registration to see every test, the failure items, the advisories and the mileage at each test.
Written by James Parry. Last reviewed 11 November 2026 against the current DVSA MOT inspection manual. Contains public sector information licensed under the Open Government Licence v3.0.