MOT Failure Categories
Which cars fail brakes the most? Who has the worst suspension? Explore failure rates by category across thousands of models.
Data from official DVSA MOT testing records
Lamps, reflectors and electrical equipment
This category covers all exterior lighting — headlamps, indicators, brake lights, fog lamps, number plate lights, and reflectors. Bulb failures are the single most common reason for MOT failure.
Noise, emissions and leaks
This covers exhaust emissions testing, excessive noise from the exhaust system, oil or fuel leaks, and catalyst efficiency. Diesel and petrol cars have different emission limits.
Body, chassis, structure
Body and structure failures cover corrosion, damage, or deterioration to load-bearing structural members, chassis rails, sills, subframes, and mounting points that compromise vehicle safety.
Seat belts and supplementary restraint systems
This covers seat belt condition, mounting points, buckle operation, retractor function, and webbing damage. All fitted seat belts must work correctly.
Brakes
Brake failures cover discs, pads, drums, pipes, hoses, servo operation, and parking brakes. This is one of the most critical safety categories in the MOT test.
Suspension
Suspension failures include worn bushes, damaged springs, leaking shock absorbers, corroded components, and excessive play in ball joints or track rod ends.
Tyres
Tyre failures include insufficient tread depth (minimum 1.6mm across the central three-quarters), damage to sidewalls, incorrect tyre size, and mixing of cross-ply and radial tyres.
Steering
Steering failures include excessive play in the steering rack, worn track rod ends, power steering fluid leaks, damaged steering column joints, and worn wheel bearings.
Visibility
Visibility failures cover windscreen damage, wiper blade condition, washer jet operation, and mirror condition. A chip or crack in the driver's line of sight fails the MOT.
Road Wheels
Wheel failures include cracked or damaged rims, missing wheel nuts, incorrect wheel fitment, and excessive wheel bearing play.
Identification of the vehicle
This covers vehicle identification checks including VIN plate presence, legibility, and security. The tester verifies the registration plate matches DVLA records and that the VIN has not been tampered with.
About MOT Failure Categories
Every MOT test checks your car against dozens of individual test items, grouped into categories like brakes, suspension, lights, and tyres. When a car fails, the failure is recorded against the relevant category.
We've analysed millions of MOT test results to show you which cars perform best and worst in each category. This helps you understand the weak points of any model before you buy, or know what to check before your next MOT.
All data comes from the DVSA's official MOT testing database. We only include models with at least 5,000 tests to ensure statistical reliability.
Based on DVSA anonymised MOT test data (2005–2024). Crown copyright, Open Government Licence v3.0.