The short answer
Dangerous or major means fail
Dangerous and major defects cause an MOT failure. Minor defects and advisories do not automatically fail the test, but they still identify items to repair, monitor or investigate.
Read the actual refusal notice or online result because the same vehicle can have several defect levels. A remembered warning light, tyre issue or brake symptom is not enough to predict the recorded classification.
The four recorded problem levels
MOT failure
Dangerous
A direct and immediate risk to road safety, or a serious environmental impact. The vehicle fails, and the dangerous item changes what the official guidance says about driving it away.
MOT failure
Major
A defect that may affect safety, the environment or other road users. Any major defect means the vehicle fails and needs repair before a successful retest.
Pass can still be issued
Minor
A defect with no significant effect on safety or the environment. A vehicle with only minor defects can pass, but the recorded items should still be repaired or monitored.
Not an automatic failure
Advisory
An item that is not yet serious enough to justify rejection. It is recorded to help the presenter understand what may need attention in the future.
The DVSA inspection manual contains the detailed test standards. It is written for authorised testers, so use it to understand the official categories rather than as a substitute for a professional inspection of a specific vehicle.
What can fail an MOT
GOV.UK publishes the list of car parts checked at an MOT as 21 official categories. Any of them can produce a major or dangerous defect, which is what turns a test into a failure. The groups below gather those categories into the areas most people ask about.
Brakes
Brakes
Condition, operation and overall braking performance, including ABS and electronic stability control where fitted.
Tyres and Wheels
Tyres and wheels
Tread depth, condition, size and type, plus the tyre pressure monitoring system on vehicles that have one.
Lights · Registration Plates
Lights and plates
Lamp condition and operation, headlamp aim and levelling, HID and LED requirements, and registration plate condition, security and character format.
Windscreen · Wipers and Washers · Mirrors · Horn
Driver's view of the road
Windscreen condition within the swept area, wiper and washer operation, the required mirrors or indirect vision devices, and a horn that works and is suitable.
Steering and Suspension
Steering and suspension
Condition and operation, power steering fluid level and the electronic steering components on vehicles fitted with them.
Exhaust Emissions · Exhaust System · Fuel System
Emissions, exhaust and fuel
Emissions against the standard for the vehicle's age and fuel type, exhaust system completeness and noise, catalytic converter presence, and fuel system leaks and cap sealing.
Body and Vehicle Structure · Doors · Bonnet · Seats · Seatbelts · Load Security · Towbars
Structure, doors and restraints
Corrosion, damage and sharp edges, latches and hinges, secure bonnet closure, driver seat adjustment and seat security, seat belt condition and operation, boot or tailgate closure, and towbar condition.
Vehicle Identification Number · Electrical
Identification and electrics
A single displayed VIN on vehicles registered from 1980, plus visible electrical wiring and the battery.
The test does not cover the condition of the engine, clutch or gearbox. It also does not publish a single ranked list of the most common MOT fails, so treat any “top reasons” list as general background rather than a prediction for one vehicle. Your own recorded result is the only list that describes your car.
What a pass or fail does not tell you
Not a complete mechanical inspection
The MOT covers defined road safety and environmental standards. It does not diagnose every noise, future failure or maintenance need.
Not a buying or valuation report
A result does not confirm value, ownership, finance, insurance, tax, accident history or whether a vehicle is suitable to buy.
Not a future safety guarantee
Roadworthiness can change after the test. Drivers and keepers remain responsible for the vehicle's current condition.
What to do after an MOT failure
1. Read the recorded result
Use the refusal notice or online MOT history to identify every dangerous, major, minor and advisory item. Keep the tester's wording intact when discussing repairs.
2. Arrange the necessary repairs
Ask a suitable repairer to assess the listed defects. MotRadar does not diagnose the vehicle or estimate the repair, and an MOT result does not list every possible mechanical issue.
3. Check the retest conditions
Free or reduced partial retests depend on where the vehicle is repaired, how quickly it returns and which defects are being retested. Check the current GOV.UK retest rules before relying on a fee or deadline.
4. Appeal before repairs if the result seems wrong
Discuss the result with the test centre first. GOV.UK says repairs should not be made before the appeal process is complete, because changing the vehicle may affect the official recheck.
See the current GOV.UK retest conditions and DVSA appeal process before relying on a fee, time limit or eligibility assumption.
Can you drive after a failed MOT?
Keep every condition together
GOV.UK says a failed vehicle can be taken away only if its current MOT is still valid and no dangerous problems were listed. Even when both conditions apply, the vehicle must meet minimum roadworthiness standards at all times. This general guide cannot decide whether a particular vehicle or journey is lawful or safe.
The expiry date, failure result and present condition are different questions. Read the MOT grace period and driving guide for the expired-MOT scenarios and limited official exceptions.
Frequently asked questions
Do advisories fail an MOT?
No. An advisory is not an automatic failure. It identifies something that is not yet serious enough to reject but may need attention. A separate major or dangerous defect would still cause a failure.
Can a car pass with a minor defect?
Yes. DVSA's inspection manual says a vehicle with only minor defects can pass and receive a certificate. The minor items are still recorded and should not be ignored.
Does an MOT pass prove the vehicle is safe?
No. An MOT applies defined minimum standards at the time of the test. It is not a complete mechanical inspection, valuation, purchase recommendation or guarantee of future roadworthiness.
Is an MOT retest always free?
No. A partial retest can be free or charged at a reduced rate only in specified circumstances. The repair location, return time and failed item determine which rule applies.
Can I appeal an MOT failure?
Yes. GOV.UK provides a DVSA appeal route. Discuss the result with the test centre and follow the official process before repairs are made; MotRadar cannot change or appeal a result for you.
Can I drive after a failed MOT?
Only limited conditions are described by the official guidance. Check whether the current MOT is still valid, whether any dangerous problem was listed and whether the vehicle remains roadworthy. This page cannot decide a particular journey.
Official sources
Use these primary pages to check the current classification, retest and appeal rules.
Editorial and service boundary
Last reviewed: 20 August 2026. MotRadar is independent and is not a government service, DVSA service or test centre. This is general information, not legal advice, a repair diagnosis, a road-safety assessment or personalised permission to drive.
Check the recorded evidence
Open your vehicle's MOT history
Review the available test result, defect wording, mileage and previous advisories before arranging the next step.
Check MOT historyRead the MOT grace period guide