The most common MOT failures
More than a quarter of cars fail their MOT first time. In 2025 to 2026, 27.5% of car and light van tests in Great Britain failed on the first attempt. Most of those failures are for faults that are cheap to fix, or that the driver could have spotted beforehand.
MOT failure rates by category (2025 to 2026)
| Defect category | % of all tests failing for this | % of all failure defects |
|---|---|---|
| Lamps, reflectors and electrical equipment | 10.4% | 24.9% |
| Suspension | 8.9% | 20.5% |
| Tyres | 6.2% | 12.9% |
| Brakes | 6.1% | 15.2% |
| Visibility | 4.3% | 7.7% |
| Body, chassis and structure | 3.2% | 6.3% |
| Noise, emissions and leaks | 3.1% | 5.9% |
| Steering | 1.9% | 3.6% |
| Seat belts and restraint systems | 1.0% | 1.6% |
| Road wheels | 0.4% | 0.8% |
| Identification of the vehicle | 0.3% | 0.6% |
Source: DVSA MOT testing data for Great Britain, class 3 and 4 vehicles, initial failures by defect category. 7.2% of tests found a dangerous defect and 20.3% a major defect. A failing car had 2.4 failure defects on average.
1. Lights and electrical faults
The single biggest cause of MOT failure. Common examples are a blown bulb, a headlamp aimed too high, a broken indicator lens, a faulty brake light switch or a number plate lamp that does not work.
How to avoid it: switch on every light and walk round the car. Use a reflection in a garage door or ask someone to check the brake lights. Bulbs are cheap and most can be changed in minutes.
2. Suspension
Worn bushes, broken coil springs, leaking shock absorbers and play in suspension joints. Broken springs are especially common on older cars and on roads with potholes.
How to avoid it: listen for knocks over bumps, check whether the car sits level, and have suspension advisories from the last MOT looked at before the next one.
3. Tyres
Tread below the 1.6 mm legal limit, cuts deep enough to reach the cords, bulges, and mismatched tyres on the same axle.
How to avoid it: check the tread with a gauge or the tread wear indicators in the grooves. Look along the sidewalls for cuts and bulges. If the last MOT said a tyre was close to the limit, replace it before the test.
4. Brakes
Low brake efficiency, worn discs and pads, corroded brake pipes, a weak parking brake, and ABS or brake warning lights on the dashboard.
How to avoid it: pay attention to grinding noises, a spongy pedal or the car pulling to one side. Corroded brake pipe advisories should be checked at every service.
5. Visibility
Windscreen chips or cracks in the driver's line of sight, worn wiper blades, empty washer bottles and damaged mirrors.
How to avoid it: top up the washer fluid (an empty bottle can fail), replace smeary wiper blades, and get chips repaired before they spread. Damage of 10 mm or more in the area directly in front of the driver, or 40 mm or more elsewhere in the swept area, is likely to fail.
6. Body, chassis and structure
Excessive corrosion in load-bearing areas such as sills, sub-frames and suspension mounting points, and sharp edges from damage.
How to avoid it: structural corrosion takes years to develop, so watch for corrosion advisories and deal with them early. It is much cheaper than a fail.
7. Noise, emissions and leaks
Exhaust emissions above the limit, a blowing or noisy exhaust, and oil or fluid leaks.
How to avoid it: make sure the car is properly warmed up before the test, keep up with servicing, and fix leaks when they are first advised.
Quick pre-MOT checklist
- Every light works, including the number plate lamp and fog lamps.
- No dashboard warning lights stay on.
- Tyres have at least 1.6 mm of tread and no cuts or bulges.
- Wipers clear the screen and the washer bottle is full.
- No windscreen damage in front of the driver.
- Horn works and seat belts latch and retract.
- Number plates are clean, secure and legible.
- Last year's advisories have been fixed.
Check your last MOT's advisories in seconds with our MOT history check.
Dangerous vs major failures
In 2025 to 2026, 7.2% of car and light van tests found at least one dangerous defect, and 20.3% found a major defect. A dangerous defect means you must not drive the vehicle until it is repaired. A major defect means it cannot pass until it is fixed. See what to do after a fail.
Why older cars fail more often
Wear items such as suspension bushes, springs, brake pipes and exhaust systems deteriorate with age and mileage, and corrosion builds up over years. That is why advisories on an older car deserve attention: they show what is likely to fail next time. Use our MOT history check to see a car's advisories before you buy or before its next test.
How to use last year's advisories
Last year's advisories are the best predictor of this year's fails. Before your MOT, look up the previous test, list every advisory and minor defect, and ask your garage to check them at the next service. Fixing a worn tyre or a corroded brake pipe early is usually cheaper than paying for a retest.