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10 Most Common MOT Failures 2026: Lighting 12.75%, Tyres 10%

Around 28% of cars fail their initial MOT, with the average failed vehicle recording 2.47 separate defects. Here are the top 10 failure categories, what they cost to repair, and whether you can fix them yourself.

Failure Summary Table

#	Failure reason	% of failures	Typical repair cost	DIY?
1	Lighting and signalling	12.75%	£5-80	Yes (usually)
2	Suspension	10.67%	£100-500	No
3	Tyres	10.05%	£50-120 per tyre	Partial
4	Brakes	8.99%	£80-350	Limited
5	Driver's view of the road	8.48%	£10-350	Partial
6	Exhaust, fuel, and emissions	7.34%	£80-600	No
7	Body, structure, and general items	6.22%	£50-1,000+	No
8	Steering	4.12%	£100-400	No
9	Wheels and wheel bearings	2.89%	£50-200	Limited
10	Seat belts and supplementary restraints	2.15%	£20-200	Limited

Detailed Breakdown by Category

1. Lighting and signalling

12.75% of failures£5-80

What fails: Blown headlight bulbs, faulty brake lights, damaged indicators, number plate light out, headlight aim incorrect

DIY possible? Yes (usually)

Pre-MOT tip: Walk around the car with the engine running and check every light. Have someone press the brake pedal while you look. Most bulbs cost £5-15 and take 10 minutes to replace.

2. Suspension

10.67% of failures£100-500

What fails: Worn shock absorbers, damaged springs, worn ball joints, corroded wishbones, perished bushes

DIY possible? No

Pre-MOT tip: Push down firmly on each corner of the car and release. If it bounces more than twice, the shock absorbers are likely worn. Listen for knocking over speed bumps.

3. Tyres

10.05% of failures£50-120 per tyre

What fails: Tread below 1.6mm, sidewall damage, uneven wear, bulges, incorrect tyre size, mismatched tyres on same axle

DIY possible? Partial

Pre-MOT tip: Use the 20p coin test: insert a 20p coin into the main tread grooves. If you can see the outer band of the coin, the tyre is below the legal limit. Check all four tyres including the inner edges.

4. Brakes

8.99% of failures£80-350

What fails: Worn brake pads or discs, corroded brake lines, sticking calipers, handbrake not holding, brake fluid contamination

DIY possible? Limited

Pre-MOT tip: Listen for grinding or squealing when braking. Check the handbrake holds on a hill. Some garages offer free brake checks, which is worth doing before your MOT.

5. Driver's view of the road

8.48% of failures£10-350

What fails: Damaged windscreen (chips larger than 10mm in driver's zone, 40mm elsewhere), worn wiper blades, broken mirrors, obstructed view

DIY possible? Partial

Pre-MOT tip: Replace wiper blades (£10-20) if they smear or skip. Chips in the windscreen can often be repaired cheaply (£40-60) before they spread. Remove air fresheners and anything hanging from the mirror.

6. Exhaust, fuel, and emissions

7.34% of failures£80-600

What fails: High emissions readings, blocked DPF, failed catalytic converter, exhaust leaks, lambda sensor failure

DIY possible? No

Pre-MOT tip: Drive on the motorway for 20-30 minutes before your test. This heats the exhaust system and helps burn off deposits in the DPF and catalytic converter, improving emissions readings.

7. Body, structure, and general items

6.22% of failures£50-1,000+

What fails: Structural rust or corrosion, sharp edges, insecure body panels, damaged bumpers, boot that will not latch

DIY possible? No

Pre-MOT tip: Check the sills, wheel arches, and subframe for rust. Prod any bubbly paintwork with your finger. Structural corrosion is one of the most expensive MOT failures and most common on older cars.

8. Steering

4.12% of failures£100-400

What fails: Excessive play in the steering, worn track rod ends, leaking power steering, damaged steering rack boots

DIY possible? No

Pre-MOT tip: With the engine running, turn the steering wheel slightly. If there is noticeable movement before the wheels respond, the steering may have excessive play.

9. Wheels and wheel bearings

2.89% of failures£50-200

What fails: Worn wheel bearings, cracked alloy wheels, loose wheel nuts, damaged studs

DIY possible? Limited

Pre-MOT tip: Listen for a humming or droning noise that changes with speed, especially when turning. This typically indicates a worn wheel bearing. Jack the car up and try to wobble each wheel.

10. Seat belts and supplementary restraints

2.15% of failures£20-200

What fails: Seat belt not retracting, buckle not latching, frayed webbing, airbag warning light on

DIY possible? Limited

Pre-MOT tip: Pull each seat belt out fully and let it retract. It should pull smoothly and lock when jerked sharply. Check the airbag warning light comes on briefly at startup then goes off.

What Does a Typical Repair Bill Look Like?

The average failed MOT involves 2.47 separate defects. A typical scenario might be a blown headlight bulb (£15) plus worn brake pads (£120) plus a damaged wiper blade (£12), giving a total repair bill of around £147 plus VAT on the repair work.

However, costs escalate quickly when structural or mechanical issues are found. A car with worn suspension, corroded brake lines, and a failing catalytic converter could face a repair bill of £800-1,200+. This is why older cars cost more to MOT on average.

For a deeper look at how failure rates and costs change with vehicle age, see our failure rate by vehicle age guide.

How Likely Is YOUR Car to Fail?

Failure rates range from 20% for a 3-year-old car to over 50% for cars aged 12+. Check your risk.

Failure Rates by Vehicle Age

Frequently Asked Questions

What is the most common MOT failure?

Lighting and signalling is the most common failure category, accounting for 12.75% of all MOT defects. Most are simple fixes like blown bulbs that cost under £20.

How much does the average MOT repair cost?

The average repair bill for a failed MOT is £150-300. However, this varies enormously. A blown bulb costs £5, while a failed catalytic converter can cost £500+.

Can I drive with a failed MOT?

If the failure is classified as 'major', you can drive to a pre-booked repair appointment as long as your previous MOT certificate is still valid. If the failure is 'dangerous', you cannot drive the car at all until it is repaired.

What percentage of cars fail their MOT?

Approximately 28% of cars fail their initial MOT test. The average failed vehicle has 2.47 defects recorded.