What fails an MOT?

All passenger vehicles must pass a Ministry of Transport (MOT) exam to legally drive on British roads. The MOT exam assesses vehicle functionality, safety, and emissions output according to the latest UK standards.

Cars and vans older than three years must take this exam annually in England, Scotland, and Wales; in Northern Ireland, vehicles begin yearly MOT testing after their fourth year of registration.

To keep drivers, passengers, and pedestrians safe, the MOT exam inspects all crucial vehicle components, boot to bonnet. Cars that pass receive an MOT certificate valid for the next calendar year. Driving without an MOT certificate can result in fines, points on your licence, or even vehicle impoundment. As vehicles without MOT certification can be seen as more dangerous, they are often worth less on the resale market .

Millions of cars fail the MOT test every year. To prepare for your next exam, learn the most common causes of MOT failure and how you can set yourself and your vehicle up for success.

Key Takeaways

Most Common Failure: Lighting and signalling issues account for nearly 1 in 5 MOT failures.
Safety Essentials: Brakes, tyres (minimum 1.6mm tread), and suspension are the leading mechanical causes of failure.
Legal Consequences: Driving without a valid MOT can lead to fines, licence points, and voided insurance.
Failure Process: If you fail, you receive a VT30 report. Repairs and a retest may be needed before the vehicle is roadworthy again.
Testing Frequency: Annual tests are required for vehicles over three years old (four years in Northern Ireland).

MOT assessment criteria
Common MOT failure areas
What to do if your vehicle fails the MOT
Challenging an MOT failure
FAQs
Is it time to sell your car?

*Motorway’s free MOT Checker tool shares your vehicle’s MOT status instantly.*

What the MOT assesses

The MOT assesses four key areas of your vehicle:

Safety – This comprehensive exam ensures that all safety elements are up to Driver and Vehicle Licensing Agency (DVLA) requirements. This includes seatbelts, brakes, tyres, and dashboard warning lights .
Functionality – The MOT also tests that all car components are working properly. This helps minimise the risks of breakdowns and accidents, keeping you safe and ideally saving you money in the long run.
Identifying issues – In checking the functionality of vehicle components, the MOT can also reveal potential underlying issues. Proactively identifying problem areas helps prevent minor issues from escalating into costly replacements and can help extend the lifespan of essential car components, ensuring reliability over time.
Emissions – The MOT assesses vehicle emission levels according to the latest government standards. Compliance with emission standards reduces your car’s environmental impact; failure to comply can lead to fines, especially if you’re in an Ultra Low Emission Zone or Clean Air Zone .

When the test is complete, any issues found will be sorted into one of four categories:

Dangerous – A serious and immediate risk to road safety. Your car fails the MOT, and you must not drive it until the problem is fixed.
Major – A significant issue that affects safety or the environment. Your car fails the MOT and needs to be repaired before it is roadworthy again.
Minor – A problem that does not cause an immediate risk but should be repaired soon. Your car still passes the MOT, but the issue will be noted on your result.
Advisory – Something to keep an eye on. It is not a problem right now, but could become one in the future if left unaddressed.

Your car will only fail the MOT if dangerous or major defects are found. Minor and advisory items are recorded for your reference but will not prevent you from passing.

Not sure of your vehicle’s current MOT status, or interested in viewing its full MOT history? Try our new MOT Checker tool for a free, instant MOT scan today. You can also set reminders ahead of your vehicle’s MOT expiration date, so you’ll never have to sweat the annual deadline again.

Most common MOT failure areas

mechanic under a vehicle — *Stay in the driver’s seat by understanding the most common reasons for MOT failure.*

The MOT exam assesses core vehicle components and systems, as well as the overall condition of your car or van. According to the Driver and Vehicle Standards Agency (DVSA), the most common reasons for MOT failure, in descending order, are as follows:

Failure Category	Common Issues	Failure Rate (Approx)
Lighting & Signalling	Faulty bulbs, indicators, brake lights	~19%
Brake System	Worn pads, low fluid, responsiveness	~10%
Visibility	Cracked windscreens, worn wipers	~10%
Tyres	Tread depth < 1.6mm, bulges, pressure	High

Lighting and signalling issues

Adequate lighting is essential for road safety. According to the DVSA, lighting issues are the most common reason for MOT failure. Common culprits are faulty headlights, brake lights, indicators, fog lights, and registration plate lights. Nearly one in five cars show problems with lights and signalling during their annual MOT exams. The good news? Many of these problems require simple fixes, like regularly inspecting and replacing bulbs. Before your test, ask someone to stand outside the car while you cycle through every light, front, rear, and sides, to spot any that have blown.

Suspension faults

Suspension plays a crucial role in vehicle handling, comfort, and tyre wear. However, suspension joints, springs, and shock absorbers wear down over time. Uneven road feel or unusual noises could indicate suspension issues. One quick way to see if your vehicle has suspension issues is to push down on each corner of your car and see if it quickly settles back to the correct height. Then, consult a mechanic for a full evaluation.

Brake system failures

The brake system is critical for vehicle safety, and braking issues account for a significant number of MOT fails each year. Warning signs to watch for include a spongy or soft pedal feel, the car pulling to one side when you brake, or any grinding or squealing noises. If you notice anything unusual while braking, contact your local garage straight away and ask them to check your brake pads, discs, and brake fluid levels.

Tyre problems

Problems with tyres can literally drive you off the road. Common failures include insufficient tread depth (the minimum legal UK tread depth is 1.6mm), damage from general wear and tear or potholes, and incorrect tyre pressure.

Before your test, run through a quick check:

Tread depth – Place a 20p coin into the main grooves across the full width of each tyre. If you can see the outer band of the coin, your tread may be below the legal limit.
Condition – Look for any cuts, bulges, or cracks in the sidewalls.
Pressure – Make sure all tyres are inflated to the manufacturer’s recommended level.
Matching – Confirm that all tyres are the correct size for your car.

A few minutes spent checking can save you from a preventable fail.

Driver visibility problems

Nearly 10% of MOT failures are because of problems seeing the road. Clear visibility is essential for safe driving, but many of us drive with cracked or damaged windscreens, worn wiper blades, obstructed mirrors, or dirt or grime in our field of vision. Any chips or damage in the driver’s central view should be no larger than 10mm or no larger than 40mm in the whole of the swept area. Clean up all points of visibility ahead of your MOT exam.

Bodywork and structural faults

Common failures in the field of vehicle structural integrity are often related to rust, corrosion, and structural weaknesses. These problems are more common in older cars, but can occur in any vehicle based on environmental factors (such as weather or storage conditions) as well as accidents. Fixing bodywork damage and ensuring structural integrity are essential for passing the MOT.

Fuel and exhaust emissions

Proper fuel system function is crucial for emissions compliance. Common failures include fuel leaks, malfunctioning catalytic converters, and excessive emissions, particularly on diesel vehicles.

One practical tip: take your car on a longer drive at higher revs before the test (a motorway run is ideal). This helps warm the engine fully and clear out built-up carbon deposits that can push emissions over the limit. You should also keep an eye out for abnormal exhaust smoke and check for any visible fuel leaks around the engine bay.

Steering faults

Proper steering is vital for vehicle control. Loose steering, worn steering racks, and leaking power steering fluid all contribute to MOT failures in this category.

One thing worth knowing: power steering fluid is one of the few fluids actually checked during the MOT. The level in the reservoir needs to be at or above the minimum mark, so take a look under the bonnet before your test and top it up if needed. If you notice the steering feels heavier than usual or makes a whining noise when you turn, get it looked at by a mechanic before your appointment.

Seat belts and airbags

Your seat belts are the most important device designed to keep you safe during a collision, followed by airbags. Issues with these safety features can result in immediate MOT failure. Luckily, they only account for approximately two percent of failures per year.

Other common failures

A few other items can catch you out on MOT day. Common ones include:

Registration plates – Your plates must be clearly visible and legible. A dirty plate or a blown registration plate light is an easy fail, and an easy fix. Give them a wipe before you go.
Horn – It must produce a continuous, uniform sound. A quick test in the driveway takes seconds.
Battery – It should be securely mounted with no signs of leaking or corrosion.
Mirrors – All required mirrors must be present, intact, and adjustable.
Dashboard warning lights – Check that no warning lights are illuminated before heading to your assessment. Some, such as the airbag or engine management light, can cause an immediate fail.

Drive a Heavy Goods Vehicle (HGV), bus, or trailer? You’ll need to pass a different MOT test for larger vehicles . In addition to the above, this test also assesses if headlamp aim and if vehicles adhere to protocol for properly carrying dangerous goods.

What to do if your vehicle fails the MOT

car on ramp in a garage — *Failing the MOT is not the end of the world. But it does mean that you need to take action to fix your vehicle.*

Failing the MOT means that your vehicle did not meet the required safety or environmental standards. Whether you can drive it away depends on two things:

If your previous MOT is still valid and no ‘dangerous’ defects were found, you can drive your car away from the test centre. However, it must still meet minimum roadworthiness standards at all times, and you should arrange repairs as soon as possible.

If your previous MOT has expired, or dangerous defects were found, you must not drive the car until the issues are fixed. Driving with a dangerous defect can result in a fine of up to £2,500, a driving ban, and three penalty points on your licence.

So, if your car or van does not pass the MOT test, it’s time to act . Review the VT30 comprehensive MOT failure report from the testing centre, which details the specific issues preventing your vehicle from being roadworthy.

Then, schedule repairs with a reliable mechanic. Many repairs can be done at the same testing centre where you had your MOT. Remember to keep all invoices as proof.

Finally, schedule an MOT retest to ensure that all identified issues have been fixed. Be sure to bring your repair invoices to the MOT retest as you could qualify for a partial or full retest fee exemption. Your vehicle must pass the retest to be able to legally hit the road again.

How to challenge an MOT failure

If you think your MOT result is wrong, you have the right to challenge it. Here is how to go about it:

Review your VT30 report – This is the detailed failure report from your testing centre. It lists every defect found, so read through it carefully.
Get a second opinion – Take your car to a qualified mechanic or another MOT testing centre for an independent assessment. They can tell you whether the defects listed are genuine and worth disputing.
Check the official guidelines – The DVSA publishes the full MOT testing standards online. Comparing these against your report can help you spot where a tester’s judgement may differ from yours.
Submit an appeal – If you still believe the result is unfair, you can appeal through DVSA. This must normally be done within 14 working days of the test and the appeal will involve a re-examination by a different tester.

Most disputes come down to borderline judgements rather than clear-cut errors, so getting an independent assessment first can save you time.

FAQs

How can I best prepare for the MOT?

The best way to prepare for your car or van’s MOT is to assess all key vehicle components ahead of your exam. In addition to regular car maintenance and giving your car a nice wash, you should check your lights and tyres, test your brakes, and make sure all of your paperwork is in order. Visit our MOT guides for more.

Do garages fail MOT on purpose?

No, UK garages should never intentionally fail vehicles on their MOT exams. However, there may be discrepancies in judgement on cars’ roadworthiness. Ensure compliance by choosing reputable garages and understanding MOT criteria .

Can I drive my car after a failed MOT?

It depends on the type of fault found and whether your existing MOT certificate is still valid.

If your current MOT has not expired and no ‘dangerous’ defects were recorded, you can drive the car away, but you must get it repaired before it can pass a retest.

If dangerous faults are listed, you cannot legally drive the car until those faults are fixed. Driving with a dangerous defect can result in a fine of up to £2,500, three penalty points, and a driving ban.

Check your full guide to what happens if your car fails its MOT for a step-by-step breakdown of what to do next.

What are instant MOT fails?

Some faults cause an automatic fail the moment the tester spots them. These are classed as ‘dangerous’ defects, meaning the car poses an immediate risk on the road.

Tyres with exposed inner plies or steel belt, cuts, bulges, or a mismatch in size between opposite tyres
A windscreen crack or chip larger than 10mm in the driver’s direct line of sight
Brakes that provide little or no stopping force
No working headlights
A dashboard warning light indicating a serious system fault

If your car receives a dangerous defect, you cannot legally drive it until the fault is repaired and the car passes a retest.

Does a failed MOT flag up?

Yes, a failed MOT is recorded in the DVSA database. Drivers are also issued a failure report outlining identified issues with the car. It’s important to rectify the issues as soon as possible and schedule an MOT retest; only after passing this retest will your vehicle be considered legally roadworthy again.

Is your insurance invalid without MOT?

Operating a vehicle without a valid MOT breaches legal requirements and may void your insurance policy. In the event of an accident, you could be personally liable for any damages and legal costs.

Check your car insurance details for the most accurate information.

How can I check my MOT status?

With Motorway’s new MOT Checker , it’s never been easier to know the status of your vehicle’s MOT .

Simply enter your vehicle registration number into our free tool and click ‘Check MOT’. You’ll get an instant response indicating if your MOT is valid, as well as a countdown until your current certificate runs out.

With the MOT Checker, you can also explore your vehicle’s full MOT history and set reminders for when to schedule your next MOT exam.

Can you sell a car without an MOT?

Yes, you can sell a car if it doesn’t have a valid MOT. However, this will be much more difficult.

Lacking an MOT certificate will likely reduce both your potential buyer pool and your vehicle’s sales price as buyers are shopping for safe transport. Since their roadworthiness has not been verified, cars that do not have valid MOT certificates carry an additional element of risk and may seem like a riskier investment. Similarly, cars that have failed their MOT are more likely to be classified as Cat D write-offs and could be dangerous!

If your car fails the MOT test and you’re looking to get rid of it, another option could be to sell it for scrap .

How common is it to fail an MOT?

More than one in three cars fails its MOT at the first attempt. According to DVSA statistics, over 36% of cars fail first time, equivalent to around 7.8 million tests, and the average failure involves nearly three separate defects.

Lighting faults are the single most common cause, accounting for close to 30% of all defects recorded. The good news is that many of the most common failures are straightforward and inexpensive to fix before your test.

Use our free MOT Checker to view your car’s full MOT history and see whether past failures reveal any patterns worth addressing before your next test.

Is it time to sell your car?

Want to learn more about owning, maintaining, and selling your car?

Check out more of our guides here, covering everything from finding buyers, to negotiating a good price, and completing payment safely.

The information provided on this page is for general informational purposes only and should not be considered as professional advice.