The 10 Most Common MOT Failure Reasons (And How to Avoid Them)

Written by John Brookes, Director, Crane Bank Garage Chester

23rd September 2026

We carry out between 150 and 200 MOT tests every month here at Crane Bank Garage on Hartford Way, Chester. After more than 50 years in the business, I have a very clear picture of what causes the most failures, and more importantly, what drivers can do to avoid them.

The truth is that many of the most common MOT failures are preventable. A simple check before you come in can save you the inconvenience of a retest and in some cases a repair bill for something that could have been spotted earlier.

Whether you are coming to us from Blacon just down the road, driving across from Handbridge, or making the trip in from Saughall or Curzon Park, this advice applies to every car and every driver in Chester.

1. Lighting and signalling

Faulty lights are the most common MOT failure reason in the UK year after year. Every light on the vehicle is checked, including headlights on full and dipped beam, brake lights, indicators, hazard lights, fog lights and number plate lights. A single blown bulb can cause a failure.

Walk around the car before you come in and check every light is working. It takes two minutes and could save you a trip back for a retest.

2. Tyres

Tyres below the legal minimum tread depth of 1.6mm, or with visible damage such as bulges, cuts or exposed cord, will cause a failure. Tyre-related issues are one of the most consistent problems we see at our Chester test centre.

I always tell Chester drivers to use the 20p test before their MOT. Insert a 20p coin into the tread groove and if the outer rim is visible, your tread may be at or below the legal limit. If you are not sure, bring the car in early and we will check them for you.

3. Brakes

Worn brake pads, corroded discs or a brake imbalance are all common failure points. If your brakes are squealing, grinding, or pulling to one side when you apply them, please do not wait until your MOT to get them looked at. Brakes are a safety issue first and foremost.

One of our Chester customers said it well: “Great service. Professional and honest. When a main dealer quoted me for work the car didn’t need, Crane Bank gave me a straight answer.” That is exactly the approach we take with brakes and every other aspect of your vehicle.

4. Suspension

Worn suspension components including shock absorbers, springs and steering joints are a significant cause of failures across our Chester test centre. Symptoms to watch for include excessive bouncing after going over a bump, uneven tyre wear, or a pull to one side when driving on Chester’s roads.

5. Emissions

A car producing excessive emissions will fail its MOT. This is particularly relevant for older diesel vehicles and something we see regularly in Chester given the age of many vehicles on the road. Keeping up with regular servicing, including air filter and oil changes, is the best way to keep emissions in check.

6. Windscreen and wipers

A chip or crack in the driver’s critical viewing area of the windscreen will cause a failure, as will wiper blades that are not clearing the screen properly. Both are relatively inexpensive to address before your test.

7. Exhaust

An excessively noisy exhaust, a leak, or a faulty catalytic converter will all cause a failure. If your exhaust sounds different from usual or has started rattling over the Chester streets, get it checked before you come in for your MOT.

8. Dashboard warning lights

An illuminated engine management light will cause an MOT failure in most cases. If you have any warning lights showing when you bring the car to us on Hartford Way, our tester will see them. It is always worth calling us beforehand on 01244 317191 so we can advise you on next steps.

9. Horn

A non-functioning horn is a simple but surprisingly common failure. Give yours a test before you come in.

10. Seatbelts

Every seatbelt in the vehicle is checked, not just the driver’s. Make sure all belts clip in securely, retract smoothly and show no signs of fraying or damage.

What happens if my car fails at Crane Bank?

If your car does not pass its MOT with us, we offer a free retest within 14 days. Our team will sit down with you and explain exactly what needs to be done, with no pressure and no unnecessary work recommended. Small items such as bulbs and wiper blades are replaced at no extra labour cost.

As Brian Pickering, one of our long-standing Chester customers, told us: “Service and MOT performed to the usual high standard. All sorted for another year of problem free motoring.”

That is exactly what we aim to give every customer who comes through our doors on Hartford Way.

Book your MOT in Chester

Crane Bank Garage is a DVSA authorised MOT test centre at Hartford Way, Sealand Road, Chester, CH1 4NT. We have been looking after Chester drivers since 1974 and I would be delighted to look after your car too.

Call 01244 317191 or book online here.