Drawn from 23.8 million first-time MOT tests in Great Britain, 2025. Tyres and brakes lead by a distance; the rest is mostly suspension, steering and, as cars age, corrosion.
The faults that come up most in each area, by the share of first MOTs at ages 6 to 9 where each was recorded, across every model we track. Rough guide costs are a UK ballpark and vary a lot by car, part quality and garage.
The same data split by how old the car is.
Mostly wear: tyres, brakes and the odd bulb.
Worn suspension and springs climb, and corrosion spreads across the underside, as the miles and years add up.
Every model has its own weak spots.
Tyres. Worn tread and damaged tyres are the single most common reason cars fail, followed closely by brakes. Both are wear items that build up between services.
Across millions of MOTs the top faults are worn tyres, worn brake discs and pads, tired suspension joints and shock absorbers, split steering gaiters, and, on older cars, corrosion. Lights and wipers fail often too but are cheap to fix.
As cars pass ten years old, corrosion and worn suspension climb the list, while the wear items that catch younger cars stay common. The age section on this page shows the shift.
Most are not. Bulbs, wipers and gaiters are cheap; tyres and brakes are moderate; corrosion needing welding is the one that can get expensive. Each fault below carries a rough range.