Why Did My Car Fail Its MOT? The Top 10 Reasons in 2026

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Around 30% of UK cars fail their MOT first time, according to DVSA figures. The frustrating part? Most of those failures could have been spotted (and fixed) for a few pounds before the test. Here are the ten most common MOT failure points and what you can check yourself this weekend.

1. Lighting and signalling (around 19% of failures)

The single biggest reason cars fail. A blown bulb costs £5 and 10 minutes to fit, but counts as a MAJOR fail. A cheap spare bulb kit in the glovebox means you can swap one the day before the test.

• Walk around the car with the lights on — headlights (dipped and full beam), sidelights, fog lights, brake lights, indicators, number plate light.
• Ask someone to press the brake pedal while you check the rear.
• Check indicators front and back, both sides.

2. Suspension (around 13% of failures)

Worn shock absorbers, broken springs, knackered bushes. Hard to spot yourself, but if the car bounces more than once after you push down on a corner, suspension is likely tired.

3. Brakes (around 10% of failures)

Worn pads, warped discs, sticking calipers, or a soft pedal. Listen for grinding or squealing when braking. If the car pulls to one side under braking, that’s a fail.

4. Tyres (around 7.5% of failures)

UK legal minimum tread depth is 1.6mm across the central three-quarters of the tyre. Use a tread depth gauge (a couple of pounds) or the 20p coin test — if the outer rim of a 20p is visible in the main grooves, your tyres are below the legal limit.

5. Driver’s view of the road

Chipped windscreen in the driver’s line of sight, dangling air fresheners, or wiper blades that smear instead of clear. A chip larger than 10mm directly in the driver’s view fails. A chip larger than 40mm anywhere on the windscreen fails.

6. Number plate

Faded, cracked, dirty, missing letters, wrong font, or stylised plates all fail. The plate must be clean, secure, and clearly readable in the standard Charles Wright font.

7. Mirrors

Cracked, missing, or insecure mirrors. Both wing mirrors and the interior mirror must be present and undamaged.

8. Seatbelts

Fraying, slow to retract, or the buckle doesn’t latch firmly. The tester will pull each belt sharply to check it locks. Every belt in the car gets checked, including the rear ones.

9. Wipers and washers

Cracked or torn blades that don’t clear the screen properly, or empty washer fluid. Replacement wiper blades take two minutes to fit, and topping up with screenwash before you take it in is the cheapest fix on this list.

10. Exhaust emissions

Especially for older diesels. If the engine management light is on, the car will fail before it even gets to the emissions test.

The 30-minute pre-MOT check

1. Walk around with all lights on — check every bulb.
2. Check tyre tread on all four wheels with a 20p coin.
3. Top up washer fluid.
4. Test the horn.
5. Check the wipers clear the screen properly.
6. Make sure the number plate is clean and undamaged.
7. Look for any warning lights on the dashboard when the engine is running.

Worth doing the weekend before your test — could save you a re-test fee and a wasted day. And while you’re giving the car some attention, it’s a good moment to fit a dash cam if you haven’t already — our UK dash cam buyer’s guide covers the best picks from £35 up.

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The pre-MOT checklist kit

Five cheap items that cover the most common avoidable failures — around £35 all-in, less than a single MOT re-test:

• Spare bulb kit (~£10) — blown bulbs are the #1 MOT failure
• Wiper blades (~£10) — smeary blades are a fail
• Tread depth gauge (~£3) — check all 4 tyres in seconds
• Screenwash 5L (~£5) — an empty washer bottle fails
• Tyre pressure gauge (~£8) — spot slow punctures early

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