MOT checklist: what is checked and why cars fail
The MOT checks your lights, brakes, tyres and wheels, steering and suspension, seatbelts, windscreen, wipers and washers, mirrors, horn, number plates, body and structure, exhaust and emissions, plus the warning lamps for systems such as ABS, airbags and the engine. It does not check the condition of the engine, clutch or gearbox.
More than a quarter of cars fail first time. DVSA figures for April 2025 to March 2026 show an initial fail rate of 27.5% across 33.3 million tests on cars and light vans, and many of those failures were things an owner could have spotted on the driveway. This checklist covers what is tested, why cars fail and the checks worth making before you book.
Why cars fail the MOT: the latest DVSA figures
Lights cause the most failures, and tyres cause the most dangerous ones. The table shows how often each area of the test recorded a defect in the 2025 to 2026 financial year, for class 3 and 4 vehicles, which are mainly cars.
Area of the test | Tests with a defect in this area | Share of all defects found |
|---|---|---|
Lamps, reflectors and electrical equipment | 10.4% | 24.9% |
Suspension | 8.9% | 20.5% |
Tyres | 6.2% | 12.9% |
Brakes | 6.1% | 15.2% |
Visibility (windscreen, wipers, washers, mirrors) | 4.3% | 7.7% |
Body, chassis and structure | 3.2% | 6.3% |
Noise, emissions and leaks | 3.1% | 5.9% |
Steering | 1.9% | 3.6% |
Seatbelts and airbags | 1.0% | 1.6% |
Two more numbers from the same DVSA dataset are worth knowing. Tyres accounted for 60.6% of all dangerous defects and brakes for 28.8%, so nine in ten dangerous faults come from those two areas. And a failed car had 2.4 defects on average, which is why one problem found on the driveway often hides another.
The trend is improving. The initial fail rate for cars and light vans has fallen in each of the last two years, from 28.6% in 2023 to 2024 to 27.5% in 2025 to 2026.
The MOT checklist: ten minutes on the driveway
You do not need tools for most of these checks, just a helper for the lights and a coin or tread gauge for the tyres.
Lights and indicators
Walk round the car with someone working the switches: dipped and main beam, sidelights, front and rear indicators, hazard lights, brake lights, fog lights, reversing lights and the number plate lamp. Check each lens for cracks and the correct colour. A blown bulb is one of the easiest fails to avoid.
Tyres and wheels
Car tyres need at least 1.6mm of tread across the central three quarters of the tread, all the way round. Look for cuts deep enough to show the cords, and for lumps or bulges, which are a dangerous defect. Tyres on the same axle must be the same size and type of construction. On cars first used from 1 January 2012, a tyre pressure monitoring system that is malfunctioning or obviously not working is a major defect, so a lit tyre pressure warning is worth investigating first.
Windscreen, wipers and washers
The tester pays most attention to zone A, a strip 290mm wide centred on the steering wheel within the area the wipers sweep. Damage larger than 10mm across in zone A, or larger than 40mm elsewhere in the swept area, counts against the car. Wiper blades must clear the screen, and washers that do not work or do not deliver enough fluid to clear the screen are a major defect, so top up the screenwash before the test.
Brakes
Check the brake fluid level against the marks on the reservoir and that the parking brake holds the car on a slope. Listen for grinding and feel for pulling to one side. The tester also checks pipes and hoses for corrosion and damage, which you cannot see without lifting the car.
Mirrors, horn, seatbelts and seats
Mirrors must be secure and usable, the horn must work with a steady tone, and every seatbelt should pull out freely, retract and latch. Check the driver's seat locks firmly in position.
Number plates and doors
Plates must be clean, secure, legible and correctly made, with standard characters and spacing. Doors, the bonnet and the boot must open and close properly.
Leaks and exhaust
Look under the car after it has been parked. A fluid leak that forms a pool more than 75mm across within five minutes of the engine idling is a fail. The exhaust must be secure and leak free, and on a diesel with a particulate filter, any visible smoke from the exhaust during the emissions check is a major defect.
Dashboard warning lights that fail an MOT
A warning lamp that shows a fault is itself a reason to fail on many modern systems. Check your dashboard after the engine starts and before the test:
Warning lamp | MOT result if it shows a fault |
|---|---|
Engine malfunction lamp (engine management light) | Major. Applies to petrol cars first used from 1 July 2003 and diesels from 1 July 2008 |
ABS | Major |
Electronic stability control (ESC, ESP or DSC) | Major |
Airbag and restraint system (SRS) | Major. A lamp showing the passenger airbag is switched off is not a fault |
Electronic power steering | Major |
Electronic parking brake | Major |
Tyre pressure monitoring system | Major, on cars first used from 1 January 2012 |
Brake fluid warning | Minor |
Brake pad wear warning | Not a reason to fail on its own |
A warning light needs a diagnosis, not a guess. Reading the fault codes before the test tells you whether the cause is a sensor, a wiring fault or a part that needs replacing, and it avoids a fail and a retest.
What the MOT does not check
The MOT tells you the car met the legal standard on the day of the test. It does not look at the condition of the engine, clutch or gearbox, and it does not change the oil, filters, brake fluid or spark plugs. A car can pass its MOT and still be overdue a service, which is why many owners book the two together.
Your MOT result: dangerous, major, minor and advisory
Dangerous: the car fails and must not be driven until it is repaired. Driving it can lead to a fine of up to £2,500, a driving ban and three penalty points.
Major: the car fails. You can drive it away only if the current MOT is still valid and the car remains roadworthy, and it must be repaired.
Minor: the car passes, and the defect is recorded for you to repair as soon as possible.
Advisory: the car passes, with a note of something to monitor, such as tyres close to the limit.
If the car fails and you leave it at the test centre for repair, the partial retest is free when it happens within 10 working days. Take it away and bring it back by the end of the next working day, and many simple items, such as lamps, wipers, mirrors, number plates and tyres, are rechecked without a fee.
When to book your MOT
A car needs its first MOT by the third anniversary of its registration, then every year. You can test up to a month, minus a day, before the current certificate runs out and keep the same renewal date. If it runs out on 15 May, the earliest test that keeps the date is 16 April.
Check your expiry date on the GOV.UK MOT history service, where you can also sign up for a free reminder. Driving without a valid MOT can bring a fine of up to £1,000, and once it has expired you may only drive to a test that is already booked or to a garage for repairs.
Notes for Mercedes-Benz, Land Rover and Jaguar owners
Premium cars carry more of the electronic systems listed in the warning lamp table, so the dashboard check matters more. Three points come up often on these marques:
AdBlue on diesels: an AdBlue leak alone is not a reason to fail, but a fault in the AdBlue system that lights the engine malfunction lamp is a major defect. Our guide to the Mercedes AdBlue warning explains the messages.
Air suspension: a Range Rover sitting low on one corner or showing a suspension message should be diagnosed before the test, because suspension is the second largest source of MOT defects. See our guide to the Range Rover suspension fault warning.
Electronic parking brakes: fitted to many recent models, and a lit malfunction lamp is a major defect.
MOT checklist questions
How long does an MOT take?
The test itself usually takes around an hour. Add time for any repairs if the car fails.
Does a dashboard warning light fail an MOT?
For many systems, yes. A lit engine, ABS, airbag, stability control, power steering, electronic parking brake or tyre pressure warning that shows a fault is a major defect.
Can I fail my MOT for an empty screenwash bottle?
Yes. Washers that do not work, or do not provide enough fluid to clear the windscreen, are a major defect.
What is the minimum tyre tread for an MOT?
1.6mm across the central three quarters of the tread, around the whole tyre, for cars.
Can I get my MOT done early?
Yes. Up to a month, minus a day, before expiry and you keep the same renewal date. Earlier than that, and the next expiry date moves to a year, minus a day, from the pass.
What is the most common reason for MOT failure?
Lamps, reflectors and electrical equipment. In 2025 to 2026 they accounted for a quarter of all defects found on cars and light vans, according to DVSA.
Book your MOT near High Wycombe
Wheels VT carries out class 4 MOT tests for £52 at Southside Farm, Wooburn Green, High Wycombe. That is below the £54.85 legal maximum for a car, and MOT fees carry no VAT. Book the MOT alongside a service, from £100 plus VAT, and the car comes back tested and serviced in one visit.
See MOT in High Wycombe for details, call 01494 670922 or book online.
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