How to Prepare for Your MOT: 10 Checks to Do at Home

By Salek Tyre & Mechanic · Ashford, TW15

Around 1 in 3 cars fails its MOT first time — but the majority of those failures are for simple things the owner could have spotted and fixed beforehand. Here are 10 checks you can do at home in about 20 minutes that could save you the cost and inconvenience of a retest.

1. Check every light on the car

Lighting faults are one of the most common MOT failure reasons — and they're trivially cheap to fix. Walk around the car and check:

• Headlights (both dipped and full beam)
• Rear brake lights — get someone to sit in the car and press the pedal while you check
• Front and rear indicators — press the hazard button to check all four at once
• Reversing light (white, rear, only illuminates in reverse)
• Number plate light
• Front and rear fog lights

A single blown bulb is an instant fail. Bulbs cost a few pounds at any motor factors shop or garage.

2. Check your tyre tread depth

The UK legal minimum is 1.6mm across the central three-quarters of the tyre. Use a 20p coin: if the outer band is visible when inserted into the grooves, the tread is likely at or below the limit. Check all four tyres, in several places — tyres can wear unevenly. See our guide: When do your tyres need replacing?

3. Check tyre pressures

Tyres must be inflated to the correct pressure — over- or under-inflated tyres can cause an advisory. The correct pressures are usually on a sticker inside the driver's door jamb or in your owner's handbook. Check how to do this: How to check your tyre pressure.

4. Check tyre condition (not just tread)

Run your hand around the sidewall of each tyre and inspect visually for cuts, bulges, cracks or embedded objects (nails, screws). A bulge means internal damage and will fail the MOT — don't drive on it, get it replaced immediately.

5. Check your windscreen wipers

Switch them on (with screen wash) and watch them work. They must clear the screen evenly without streaking or squeaking over missed patches. Wiper blades are inexpensive and take two minutes to replace.

6. Check for windscreen chips or cracks

The tester divides the windscreen into zones. A chip or crack in Zone A (the 290mm band directly in the driver's line of sight) will cause a failure if it's larger than 10mm. Chips outside Zone A fail if larger than 40mm. Most chips can be professionally repaired for under £30 before the test — cheaper than a new windscreen and cheaper than a retest.

7. Check the horn

Give the horn a quick press. It must sound clearly. This is checked during the MOT and a non-working horn is a straightforward fail — one that's easy to forget to check at home.

8. Check dashboard warning lights

Turn the ignition on (not starting the engine) and note any warning lights. Then start the car and check again — they should all extinguish within a few seconds of the engine running. An engine management light (EML) that stays on is an automatic MOT failure, as it indicates a fault that could affect emissions. Have the fault codes read before your test.

9. Check the handbrake

Park on a gentle slope, apply the handbrake, and put the car in neutral. It should hold without creeping. If it feels spongy, needs more clicks than usual, or doesn't hold firmly, get it checked before the test.

10. Check your number plates

Both front and rear plates must be clean, undamaged, properly lit (rear only), firmly attached, and show the correct registration. A cracked, faded or missing plate will fail the MOT — and is easily sorted beforehand.

Bonus: top up your fluids

Engine oil, coolant and screen wash won't directly fail an MOT, but low oil can affect emissions readings and a low screen wash reservoir will flag as an advisory. Top them up the night before your test — it takes five minutes.