29% of cars that get MOT tested fail – according to the latest DVSA test data.
So what's causing all these cars to crash out of their MOT tests? And what can you do to avoid being one of the unlucky ones?
This guide will walk you through the most common MOT failures and what to watch out for.
Most common MOT fails by category
Here's a list of the 10 most common MOT failures and the quick checks you can do to avoid them:
| Category | Failure rate | Includes | How to avoid |
| Lamps, reflectors and electrical equipment | 11.41% |
- Headlights
- Brake lights
- Other exterior lights e.g. indicators, DRLs
- Wiring
- Battery
- Trailer sockets (if fitted)
|
- Replace any blown exterior lights (if possible)
- Replace 12V battery if it fails
- Get any further electrical problems fixed by a professional
|
| Suspension | 9.08% |
- Springs
- Shock absorbers
- All arms, rods, bushes etc.
|
- Listen for odd noises over bumps or when cornering
- Have worn suspension parts replaced at a service centre
|
| Brakes | 6.85% |
- Discs, pads, drums and shoes
- Parking brake
- Brake fluid
- ABS system
|
- Feel for poor braking or listen for loud squeaks
- Have worn brake parts replaced at a service centre
|
| Tyres | 6.53% |
- Tread depth
- Tyre condition/damage
- Correct tyre fitment
- TPMS function
|
- Check for tyre wear or visible damage
- Replace bad tyres before testing
|
| Visibility | 4.47% |
- Windscreen and exterior glass
- Wipers
- Windscreen washers
|
- Check glass for chips and cracks
- Replace if necessary
- Check wipers work
- Top up screenwash and check it works
|
| Body, chassis and structure | 3.63% |
- Body condition
- Bumpers
- Doors
- Damage or serious corrosion on structure
- Exhaust system
- Fuel system
- Transmission and driveshafts
- Spare wheels and tow bars
|
- Look and listen for any loose, rattling parts
- Have any loose or broken parts replaced
- Check spare wheels, tow bars and other accessories are secure
- Serious corrosion may need expensive repair work
|
| Noise, emissions and leaks | 3.33% |
- Engine noise
- Exhaust noise
- Emissions control equipment eg. catalytic converter
- Fluid leaks
|
- Check for damaged or missing sound deadening
- Check for damaged or leaking exhaust
- Don't remove or tamper with emissions control equipment
- Check for leaks
|
| Steering | 2.14% |
- Steering linkage
- Power steering system
- Steering play
|
- Feel for any play (looseness) in the steering system
- Have any broken steering system parts replaced
|
| Seat belts and supplementary restraint systems | 1.02% |
- Seat belts
- Seat belt pre-tensioners and load limiters
- Airbags
|
- Check seat belts for damage
- Check load limiters work (tug the belt so it locks)
- Check for airbag warning light
|
| Wheels | 0.39% |
- Wheel rim damage
- Wheel hub, studs and nuts
|
- Check for missing wheel nuts
- Inspect rims for damage
- Feel for any wobble through steering
|
Source: DVSA
What can cause a car to fail an MOT?
As you'll find in the list above, there's plenty of different things a car can fail an MOT for. By far the most common – 11.4% of all failures – are for problems with the vehicle's exterior lights or electrical systems. Thankfully, these are often some of the easiest to fix with just a new bulb or replacement 12V battery needed.
The next most common failure – 9.1% – are for suspension problems. This could include things like damaged or fractured springs, worn-out shock absorbers, or failed bushings. These are also usually fairly easy to fix, with most suspension parts being fairly easy to access and swap out.
Beyond these areas, many cars fail for brakes and tyres – 6.9% and 6.5% respectively. These categories account for the greatest proportion of MOT failures classed as 'dangerous' because they're considered safety-critical items.
Will a cracked windscreen fail an MOT?
Generally speaking, yes. If your windscreen is damaged badly enough that it cracks, that'll almost certainly cause an MOT failure. You'll also fail the MOT test if your side or rear window are damaged or obscured enough that it significantly affects the driver's view.
The MOT test defines two areas on the windscreen – the 'swept area', which is the total area wiped by the wipers and 'Zone A', which is a 290mm-wide column within the swept area centred on the steering wheel, i.e. the main driver's view. You're allowed damage measuring up to 40mm in the swept area, but this drops to 10mm within Zone A.
MOT failure types
What are dangerous MOT faults?
A dangerous MOT fault means it's no longer safe to continue using the vehicle until the problem is fixed. The most common dangerous MOT faults are for worn-out or damaged tyres.
If your car has a dangerous MOT fault that can't be fixed at the MOT centre, the only legal way to get it home or to another service centre is to have it towed. You must have the problem fixed and the car re-tested before it can legally be driven again.
What are major MOT faults?
A major MOT fault means there's a problem with your car that's so serious that it failed its MOT. However, unlike a dangerous fault, you can drive the car away to get the problem fixed, and then drive back to an MOT test centre to have the car re-tested.
What are minor MOT faults?
A minor MOT fault means there's something wrong with your car that you'll need to address quickly, but it's not serious enough to fail an MOT test. Examples include tyres with low tread or brake pads that are nearly worn out.
Time to swap to a newer car?
If your old motor is finding it harder to pass its MOT each year, you might want to swap to a newer, lower-mileage car for an easier experience. Check out thousands of nearly new and used cars for sale at Motorpoint.
MOT failure FAQs
According to the DVSA, the most common MOT failures are for lighting and electrical equipment. That includes problems like blown bulbs, damaged or leaking batteries, or dodgy electrical connections.
Almost always yes, a windscreen crack will lead to an MOT failure. You're only allowed damage measuring up to 10mm within a 290mm-wide area centred on the steering wheel, which most cracks will easily exceed. Even if the crack isn't directly in front of the driver, you're only allowed damage measuring up to 40mm.
Yes. If there's no screenwash in your car, MOT testers won't be able to check that your windscreen washers work properly, which will count as a major fault. Note that you're not technically failing for the lack of screenwash, but because testers can't check the washer system clears the screen properly.
Topping up your screenwash – even if it's just with water – is a quick and easy way to avoid an annoying MOT failure.
Yes. If your vehicle was originally fitted with a rear-view mirror, it'll fail an MOT test if this mirror is missing. This doesn't apply to vans and other vehicles that did not include a rear-view mirror from the factory.
If your rear-view mirror is damaged or partially obstructed, this might get recorded as a minor fault. Damage or obstruction that means the mirror no longer works will count as a major fault.
This depends on the extent of the damage to your door mirror. If the view through the mirror is significantly affected by the damage, your car will probably receive a major fault and fail its MOT test. Should the tester determine the damage doesn't really affect the operation of the mirror – e.g. minor cracking – then this might only be recorded as a minor fault that won't constitute an MOT failure.
