Every year, the most common MOT failure items are not mysterious mechanical faults – they are lights, tyres, brakes, suspension and visibility. Many of them can be spotted in ten minutes on your driveway. This guide lists the most common reasons cars fail the MOT and how to avoid each one.
1. Lights and signalling
Lighting faults are consistently among the most common MOT failure reasons – and the easiest to prevent. Testers check headlights (including aim), sidelights, indicators, hazard lights, brake lights, fog lights, reversing lights and the number plate light.
How to avoid it: ask someone to stand outside while you test each light, or use the reflection in a garage door or shop window. Replace blown bulbs before the test. If your headlights are cloudy or yellow, headlight restoration can restore their output.
2. Suspension
Worn shock absorbers, broken springs, worn bushes and damaged suspension arms are frequent failures, especially on roads with potholes.
How to avoid it: listen for knocks over bumps, check whether the car leans or bounces excessively, and look for uneven tyre wear. A garage can inspect the suspension before the MOT. After a hard pothole hit, consider a wheel alignment check.
3. Brakes
Worn pads and discs, uneven braking force, leaking hoses and a weak handbrake are common failure items.
How to avoid it: watch for squealing, grinding, vibration through the pedal or a car that pulls to one side when braking. Read brake pads and discs: warning signs.
4. Tyres
Tread below 1.6 mm, cuts, bulges and incorrect tyre sizes all mean a fail – and illegal tyres can cost up to £2,500 and three points each if you’re stopped. See our guide to UK tyre law.
5. Driver’s view of the road
Windscreen damage in the driver’s line of sight, worn wiper blades, an empty washer bottle and obstructions such as stickers or items on the dashboard can lead to a fail.
How to avoid it: top up washer fluid, replace streaky wipers and get chips repaired early, before they spread. Read repair or replace your windshield.
6. Warning lights
Dashboard warning lights for the engine, ABS, airbags or power steering can mean a fail. Have the fault diagnosed first – read what the check engine light means.
7. Exhaust and emissions
Exhaust leaks, excessive smoke and emissions outside the limits are failure items. Diesel cars used mostly for short trips may have a clogged particulate filter. A long motorway drive before the test can help, but a persistent problem needs a garage.
8. Number plates, horn and seat belts
Illegible or incorrectly spaced number plates, a horn that doesn’t work and seat belts that don’t latch or retract are small things that still cause failures.
Quick 10-minute pre-MOT checklist
- All lights working and clean
- Tyres at least 1.6 mm, no damage, correct pressure
- Wipers clear the screen, washer bottle full
- No windscreen damage in the driver’s view
- No warning lights on the dashboard
- Horn works, seat belts latch
- Number plates clean and legible
- Car reasonably clean inside and out
Costs and changes
The maximum fee for a car MOT is £54.85 – see how much an MOT costs in 2026. You may also see testers photographing your car – read about the DVSA MOT photo rollout.
Find a garage near you
Kardet lists car service garages across Europe. Send a free request for a pre-MOT check or repairs and compare offers.