Every year, millions of drivers face the frustration of their car failing its MOT. For many, this comes as an expensive surprise, but in fact most MOT failures are caused by common issues that could have been spotted and resolved beforehand. With a little routine maintenance and regular visits to your local garage, you can greatly increase your chances of passing first time. Here are the main reasons cars fail their MOT, and what you can do to avoid them.
Lights and signalling
Faulty or broken lights are the number one reason cars fail MOTs. Headlights, brake lights, indicators, and number plate lights are all checked thoroughly during the test. A single blown bulb is enough to cause a fail, but this is also one of the easiest problems to fix. Checking your lights once a week and replacing bulbs promptly, or asking a mechanic to do it, can save you unnecessary hassle.
Tyres and tread depth
Tyres are another leading cause of MOT failure. The legal minimum tread depth is 1.6mm, but most garages recommend replacing tyres when they reach around 2–3mm to ensure safety, especially in wet weather. Uneven tyre wear can be a sign of poor wheel alignment or suspension issues; quick inspection at your local garage can highlight problems before they result in a fail.
Brakes and brake balance
Worn brake pads and discs reduce stopping power and can lead to a dangerous imbalance between the wheels. MOT testers check for wear, responsiveness, and performance. If you notice squeaking, grinding noises, or your car pulling to one side when braking, it’s time to book in with a trusted mechanic. Regular servicing keeps brakes in good condition and ensures they pass MOT standards.
Suspension problems
British roads take their toll on suspension systems, thanks to potholes and uneven surfaces. Faulty shock absorbers or broken springs are common causes of MOT failures. Warning signs include knocking noises, poor handling, or a bumpy ride. If you suspect suspension issues, ask a garage to carry out a pre-MOT check so they can replace worn parts before test day.
Windscreens, wipers, and washers
Clear vision is essential for safe driving, so MOT testers inspect your windscreen for chips, cracks, and damage. Anything larger than 10mm in the driver’s line of sight, or 40mm elsewhere, can result in a fail. Wipers that don’t clear the screen effectively or washer bottles that are empty will also cause problems. Replacing wiper blades or topping up washer fluid are simple fixes you can do at home.
Failing an MOT doesn’t have to be inevitable. Most of the common causes are quick and inexpensive to resolve if caught early. By carrying out basic checks and working with a trusted local garage, you can save time, money, and hassle, ensuring your car is safe, roadworthy, and ready to pass its MOT the first time around. Want more tips? Follow Trust A Garage on Facebook or X.