MOT guides
What fails an MOT? The most common reasons
Most MOT failures come down to a handful of wear-and-tear areas. Here is what the data actually shows across the UK fleet.
The most common MOT failure areas
Ranked by how often they appear across the modelled fleet, the most common areas to fail or pick up MOT work are lights and electrical, tyres and wheels, suspension and steering, emissions, engine, and exhaust, and corrosion and structure. None of these are exotic — they are the parts that wear with age and mileage, which is exactly why a pre-purchase check and routine maintenance matter so much.
Why cars fail
The MOT checks roadworthiness, not mechanical perfection. Lighting and electrical faults (a blown bulb counts), worn tyres below 1.6 mm, suspension and steering play, corroded brake pipes and structural rust are the usual culprits. Many are cheap to fix if caught early, which is what advisories are for.
How to avoid a failure
Check all your lights, top up washer fluid, inspect tyre tread and condition, and address any advisories from the previous test before you book. Buying used? The fault areas a specific model fails on most are listed on our model reliability reports.
Check any UK reg free for its full MOT history plus a statistical next-MOT failure-risk estimate.
Frequently asked questions
Lighting and electrical issues, tyres, and suspension/steering are consistently among the most common MOT failure areas across the UK fleet. Overall, about 18.7% of MOT tests result in a failure.
Across 42,216,721 MOT tests in our dataset (calendar year 2023), 18.7% failed and 81.3% passed first time.
Some, such as bulbs, wiper blades and washer fluid, are simple. Brakes, suspension, structural corrosion and emissions usually need a qualified garage.