15 Most Common MOT Failures and a Pre-MOT Checklist

The 15 faults that fail cars most often

1. Blown or dim bulbs on headlights, sidelights or number plate lights.
2. Headlight aim set too high or too low.
3. Faulty brake lights, including the high-level lamp.
4. Tyres below the 1.6mm minimum tread depth across the central three quarters.
5. Tyre damage — cuts, bulges, exposed cords or mismatched types on an axle.
6. Worn brake pads or discs, or an imbalance across an axle.
7. Corroded or leaking brake pipes and hoses.
8. Worn suspension components: bushes, ball joints, springs and shock absorbers.
9. Excessive play in steering joints or a leaking power steering system.
10. Wiper blades that smear, split or fail to clear the swept area.
11. Empty screenwash bottle or a washer jet that does not reach the glass.
12. Chips or cracks in the driver's line of sight, or obstructions such as large air fresheners.
13. Insecure, dirty or incorrectly spaced number plates.
14. Exhaust leaks, excessive noise or emissions outside the limits for the vehicle.
15. Seatbelts that are frayed, do not retract or do not latch, and warning lights left illuminated.

Your 20-minute pre-MOT checklist

1. Walk round with the ignition on and every light switched on — get someone to press the brake pedal while you look.
2. Check tread depth with a 20p coin: if the outer band is visible, the tyre is close to the limit.
3. Look for tyre damage and check pressures against the door-shut label.
4. Top up screenwash and test both washers and wipers.
5. Clean the windscreen inside and out and remove clutter from the driver's view and boot.
6. Sound the horn and try every seatbelt buckle and retraction.
7. Check the number plates are clean, secure and not faded.
8. Note any dashboard warning lights that stay on — several cause a fail.
9. Listen for exhaust blow on start-up and look for smoke.
10. Check the mileage reading so you can compare it with the recorded figure afterwards.

Fixing a bulb yourself costs a few pounds. The same bulb found at the test can cost a retest and a day off the road.

Use your MOT history as a warning list

Advisories from last year's test are a preview of this year's failures. Enter the registration on the RegPeek homepage to read the full history, and see how to read MOT history for what patterns to look for.

If something does go wrong on the day, what happens if your car fails explains the retest rules.