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10 Most Common MOT Failures 2026

Around 27% of cars fail their initial MOT, and a failed test usually records more than one defect. Here are the top 10 failure categories by share of all recorded defects, what they cost to repair, and whether you can fix them yourself.

Failure Summary Table

#	Failure reason	% of all defects	Typical repair cost	DIY?
1	Lighting and signalling	24.81%	£5-80	Yes (usually)
2	Suspension	19.94%	£100-500	No
3	Brakes	15.28%	£80-350	Limited
4	Tyres	12.94%	£50-120 per tyre	Partial
5	Driver's view of the road	8.54%	£10-350	Partial
6	Body, structure, and general items	6.19%	£50-1,000+	No
7	Exhaust, fuel, and emissions	5.82%	£80-600	No
8	Steering	3.40%	£100-400	No
9	Seat belts and supplementary restraints	1.66%	£20-200	Limited
10	Wheels and wheel bearings	0.79%	£50-200	Limited

Percentages are each category's share of all recorded defects on Class 3 and 4 vehicles. Source: DVSA MOT testing data for Great Britain (DVSA/MOT/03), April to June 2025 (2025-26 Q1). Overall initial failure rate 27.24% of tests.

Detailed Breakdown by Category

1. Lighting and signalling

24.81% of defects£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

19.94% of defects£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. Brakes

15.28% of defects£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.

4. Tyres

12.94% of defects£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.

5. Driver's view of the road

8.54% of defects£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. Body, structure, and general items

6.19% of defects£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.

7. Exhaust, fuel, and emissions

5.82% of defects£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.

8. Steering

3.40% of defects£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. Seat belts and supplementary restraints

1.66% of defects£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.

10. Wheels and wheel bearings

0.79% of defects£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.

What Does a Typical Repair Bill Look Like?

A failed MOT usually involves more than one defect. 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?

Initial failure rates climb with age, from roughly 14% for a 3-year-old car to about 35% by 13-15 years. 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 24.81% of all recorded MOT defects (DVSA, April to June 2025). 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?

Around 27% of cars fail their initial MOT test (27.24% in the latest DVSA quarter, April to June 2025). A failed test usually records more than one defect.