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MOT failure: Top 5 reasons and what to do if your car fails

Last updated: 13/11/2023 | Estimated Reading Time: 4 minutes

Having you car fail its MOT can be incredibly annoying. If you've followed our pre-MOT checklist, you'll probably have a good idea about whether or not your car will pass or fail. But even without the surprise, the repair bill you'll be lift with still won't be welcome. 

We've listed some common reasons for MOT failure in this guide, and outlined key steps you can take if your car doesn't pass its test.

In This Guide:

Top 5 reasons for MOT failure

Lighting and signalling

Lighting and signalling issues account for a whopping 18% of all MOT failures. This is despite the fact light replacements are, for the most part, some of the cheapest and easiest fixes on your car. You can change them yourself if you have the owner's manual but many garages will also change bulbs for a small fee, and some for free!

Another reason you might fail based on your lighting and signalling is if you have headlight deflectors fitted to your car for driving in europe, so make sure you remove these when you come back from the continent!

Driver's view of the road

Having cracks and chips in your windscreen which obscure the driver's view is a sure fire way to fail an MOT, but many driver's don't realise that you can also fail if you have items obscuring the view, so avoid placing stickers, phone cradles or bluetooth headsets in the windscreen for your test. Some car insurance policies will cover repairs to your windscreen, so if you have a crack it's worth checking with your insurance provider.

At least one of your wing-mirrors, as well as your rear view mirror, must be also clean and undamaged. replacement stick on mirror surfaces can be purchased very cheaply.

Your view of the road extends to your windscreen wiper blades and washers as well so be sure to fill up the fluid and test that the wipers clear the windscreen effectively before your test. The rubber on your wiper blades should be replaced, a cheap fix, if it is at all damaged or more than a year old.

Tyre condition and pressure

Around 10% of MOT fails are due to tyre issues. It's vital that tyres have the correct pressure and enough tread depth to allow you to effectively stop in the event of an emergency, so they should be regularly checked. If the tyres show any sign of damage, bulging, or the tread is less than 1.6mm your car will fail it's MOT.

Brake issues

Make sure you check your brakes before an MOT. If the braking feels spongey or the steering pulls to either side when braking it could be a sign that the pads or discs are worn and may need replacing. Dependent on the conditions you drive in, brakes can wear out quite quickly, for example in hilly areas, or last a long time if you often drive slowly and rarely have to operate them. On average brakes need replacing around every 50,000 miles.


Suspension failures are fairly common in Britain, owing to the fact our roads are often potholed and bumpy. There's not a lot you can do to predict a suspension failure, and either way it's a tough fix that you'd most likely want to have done by a professional anyway. You can maintain your suspension by driving carefully and trying not to hit every bump in the road at speed.

What happens if your car fails its MOT?

If you fail your MOT, it will be because of either a dangerous or major fault. Dangerous faults need to be repaired before the vehicle can be driven again. According to government advice: "You can be fined up to £2,500, be banned from driving and get 3 penalty points for driving a vehicle that has failed its MOT because of a ‘dangerous’ problem."

On the other hand, major faults can be taken away to be repaired, either by a specialist or yourself, if you have the know-how.

While it may feel frustrating, according to DVSA data around 1 in 3 drivers will experience a failed MOT each year. So it's not necessarily a reason to panic. In the event of a fail, your garage will issue you with a VT30 'Refusal of an MOT test certificate' with your car's details on and the reasons for the failure. You'll then present this certificate when you have a new test, having repaired the faults. 

Provided your VT30 doesn't list a dangerous fault, you can either take the car away to be repaired or leave it at the testing garage. So long as you perform the repairs within 10 days, and return to the original testing centre, they can carry out a partial retest. This means they'll only test the issues listed on the VT30 and you'll only be charged for part (usually half) of the original testing fee.

If you return the car outside of the 10 day grace period you will be charged the full MOT test cost again.

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