MOT Failure: What, Why and How?

MOT Test Failure

When your car’s MOT test is due, it can be a stressful time – especially if your vehicle fails. Between 2018 and 2019, there were 29,560,831 tests, and 26.2% MOT failures. The most common question in this scenario is: what do I do now? Here at BookMyGarage, we understand the confusion surrounding MOT failure, so we’ve created a comprehensive guide to give clarity on your next steps after an unsuccessful MOT.

The MOT checklist and what might cause your vehicle to fail.

There are many things a mechanic will check during an MOT test. Below is a list of checks included in an MOT test, what it is tested for and how it could impact your vehicle’s MOT result. More information on the MOT test process can be found here.

Lights – front, rear, fog, brake, indicators and licence plate

Do they work? 18% of all MOT failures in 2018 were due to problems with lights or signalling. Check the bulbs yourself before you go so you’re not caught out.


Will it alert other road users to your presence if required? A horn which isn’t loud enough – or doesn’t work at all – could fail your vehicle’s MOT.

Electrics & Battery

Does your vehicle have any problems starting on a cold day? If so, there could be an issue with the battery. The mechanic will check that everything is in complete working order and the electrics aren’t dangerous.

Towbar (if applicable)

Is it secure and in good condition? If your towbar is loose or damaged it could affect your vehicle’s MOT result. In addition, your engine mountings are checked to ensure they are fastened securely in position.


Do you feel in control of your vehicle’s steering? If not, there may be a fault which could fail your MOT. The mechanic will test the condition of your steering and ensure all the mechanisms work correctly.


Is anything within the suspension not doing its job properly? If your vehicle is sagging on one side, it could indicate a fault with your shock absorbers which could fail your MOT.

Brakes and handbrake

Is there any resistance when you engage your handbrake? If the answer is no, it will be deemed unsafe by the mechanic. Your brakes must have sufficient unspoiled brake fluid and be able to safely stop your car or they could be classed as a dangerous fault.

Tyres & Wheels

Are the treads legal? If they are below 1.6mm in depth, they’re automatically marked as a fail on your MOT test. Similarly, any damage on the tyres or wheels themselves or incorrect tyre pressure could constitute a failure.


Do they restrain safely? If there are any tears in the seatbelts, or they don’t extend far enough without resistance, they could be deemed as unsafe.

Body, Boot, and Bonnet

Is there any corrosion or damage? Excessive rust or sharp edges on your bodywork can be deemed as dangerous and cause your vehicle to fail its MOT.

Licence plates

Is everything present and correct? Your vehicle could fail its MOT should licence plates be missing or in poor condition.

VIN (Vehicle Identification Number)

Is there one on your vehicle? If your vehicle was registered before 1980, it probably won’t have one but a missing VIN could lead to your vehicle failing its MOT due to the implications of it being a stolen vehicle.


Would you know if your vehicle developed a serious fault? The mechanic will test all the warning lights to make sure they work when needed. If one or more doesn’t work, it could constitute an MOT failure due to the danger posed to you and other road users if a fault develops without you being aware of it.


Is it in good working order? It doesn’t matter if your speedometer is cracked – just as long as it lights up and the driver can read it. But if your speedometer isn’t working, your vehicle may fail its MOT.

Exhaust system

Is it leaking? A leaky exhaust can potentially be dangerous to the driver due to the buildup of dangerous Carbon Monoxide gases within the cabin. It must also be secure and fitted with a catalyst, (where applicable).

Fuel system

Does it leak? The mechanic will check the workings of the fuel system and ensure that the fuel filler cap can be sealed securely. Any issues with this could lead to failure due to the danger to other road users. 


Does your vehicle have enough fuel to check for this? If the mechanic suspects there isn’t enough fuel to run the engine long enough to test for emission production, they may refuse to test your vehicle. Similarly, your vehicle could fail if it doesn’t meet the emissions standards.

Windscreen & Mirrors

Can the driver see clearly? Any damage on the windscreen exceeding 10mm will immediately fail your vehicle’s MOT. Anything hanging from the rearview mirror could also fail your vehicle’s MOT if it’s deemed to be obstructing the driver’s field of view. 


Are they doing their job effectively? If your wipers don’t clean the windscreen, or there’s any damage to the wiper themselves, your vehicle could fail its MOT.

Further information about what is checked during the MOT process can be found on the Government website. You can also use our MOT test checklist down below to prepare your car for its test.

Checklist to prevent MOT Failure

What should I do if my vehicle fails its MOT test?

4 out of 10 cars fail their MOT test every year but as Corporal Jones says, ‘Don’t Panic!’. The same mechanic who failed your vehicle’s MOT can repair the faults so your car will pass when it gets retested. The exception to this is if your MOT was carried out at a council MOT test centre and it fails. They cannot carry out repairs on-site, so you would need to hire a tow truck on top of the cost of repairs at a garage. If you suspect your vehicle might not pass its MOT, going direct to a garage could be beneficial in terms of costs.

What is a retest and how do I get it done?

An MOT retest is simply another chance for your vehicle to pass its MOT, usually after repair work has been carried out on the fault which failed it the first time. Most mechanics will do the retest for free if it’s done within one day of the first test, and for a partial fee within ten working days. Waiting any longer than that – or taking your car to a different garage – could incur the full MOT fee on top of whatever repair work was necessary.

You can usually book a retest with your mechanic when they inform you that your vehicle has failed its MOT. Alternatively, you can book another MOT test through our online booking tool for free. All you need to do is enter your registration number.

What if my vehicle fails when I wasn’t expecting it to?

Sometimes, an MOT failure can come out of the blue when you thought your car was running perfectly fine. There is a process where drivers can appeal their MOT decision to the Driver and Vehicle Standards Agency (DVSA) within 14 days of a failed MOT test in the hope of overturning the decision. You will have to pay to accept an offered appointment, and no repair work can be carried out on your vehicle before this appointment. As always, it’s worth thinking carefully before appealing this decision because, although a successful appeal will result in a full or partial refund of your MOT retest cost, there is no guarantee that you have a case.

Can I drive my car if it has failed its MOT test?

The only time you can drive your vehicle after an MOT failure is if your previous MOT certificate is still valid i.e you booked your MOT test within a month, minus a day, of it expiring. This gives you the safety net of still being able to drive your vehicle, even if something is wrong with it. However, you should never ignore an MOT failure, for the safety of you and others. Your vehicle will have failed its MOT for a reason. It will do so again when your MOT certificate runs out, so fixing the fault early on and getting it retested is beneficial.

If your car no longer has a valid MOT certificate, and especially if the mechanic has found a dangerous fault under no circumstances can you drive it away before the fault is fixed. In essence, its all for the safety of you and other road users.

What if I drive my vehicle without an MOT?

There are some serious consequences to driving without a valid MOT – it’s almost like driving without insurance. If you are stopped by the police and don’t have a valid MOT, there is a fine of £1000. In addition, if they found your car to be unroadworthy, you could be fined £2500 and face a driving ban and/or three points on your licence. Those are some eye-watering numbers – so it’s not worth the risk.

Can I prevent MOT failure?

While it’s not always possible to completely prevent MOT failure due to the expertise needed to carry out some of the checks, there are some simple things you can do yourself to stand the best possible chance of your vehicle passing its MOT test. These include checking your bulbs, tyres, mirrors, and windscreen, cleaning your vehicle’s interior and exterior, and topping up screenwash levels, oil and fuel. More detail on some MOT best practices can be found here.

Nobody ever wants the worst to happen but it’s always worth being prepared. Garages will be sympathetic concerning MOT failure, but they have a duty of care to you and other road users. So when they suggest repairs, it’s best to listen to their expertise. 

Have you overpaid for your MOT in the past? Check out our directory of garages today – it’s quick, simple to use and you don’t pay a penny until after the work’s done! Avoid any MOT horror stories and compare and save using BookMyGarage today.

Mandy Weston

Mandy Weston

Mandy is an ex-mechanic, with 22 years’ experience in the motor industry. As an in-house motoring expert, Mandy is the go-to woman for any relevant questions that our customers have; both garages and drivers. From specific problems with your car to general maintenance, Mandy is a reliable source of information and advice. Her passion for motoring is a huge factor to her success and the huge wealth of knowledge that she has. She now uses her remarkable grasp of the industry to write regular content for our readers to help drivers understand their car better, avoid being ripped off by garages and save money on their motoring requirements.

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