What Happens at an MOT Test — Everything That Gets Checked
The MOT test is a minimum safety standard check that every car over three years old must pass annually. Understanding what is checked helps you prepare for your own test — and interpret a used car's MOT history more intelligently.
The Main Areas Checked
- Lights — all headlights (dip and main beam), fog lights, brake lights, reversing lights, indicators, and hazard lights must function correctly and be aimed properly
- Brakes — brake performance is measured on a rolling road for front and rear axle separately. Handbrake operation is checked. Brake pipes, hoses, and callipers are inspected for condition.
- Tyres — tread depth must be at least 1.6mm across the central 75% of the width. Tyres are checked for cuts, bulges, and correct size match. Spare tyres are not checked.
- Steering — play in the steering column, condition of the rack and track rod ends, and power steering fluid level (where applicable)
- Seat belts — all belts must retract correctly, latch securely, and show no fraying or damage
- Exhaust emissions — CO and HC levels are measured for petrol cars. Smoke opacity is checked for diesel
- Windscreen — no chips or cracks in the driver's primary vision area; wipers must clear effectively
- Bodywork — no sharp edges or protrusions that could injure a pedestrian
- Horn — must function
- VIN — the Vehicle Identification Number must be visible and legible
Fail Categories
Since May 2018, MOT failures are categorised as:
- Dangerous — immediate road safety risk. Vehicle must not be driven away. Common causes: severely worn brakes, dangerous tyres, steering failure.
- Major — vehicle must be repaired before road use. Covers most fail items.
- Minor — does not fail the test but should be monitored and repaired soon.
- Advisory — item is acceptable now but may deteriorate. Advisories are recorded in the DVSA database and visible on VEHIXA history checks.
Reading MOT History as a Buyer
When viewing a used car's MOT history, pay particular attention to repeated advisory items — they indicate the seller has been aware of a developing issue and has not addressed it. Multiple failures for the same item can signal chronic neglect. Check the mileage progression at each test — flat or decreasing mileage between tests is a strong indicator of odometer tampering.
Frequently Asked Questions
What do they check on an MOT test?
An MOT checks: lights (headlights, brake lights, indicators), brakes (performance, handbrake, condition), steering (play, power steering fluid), tyres (tread depth minimum 1.6mm, condition), seat belts, horn, windscreen wipers, exhaust emissions, bodywork (no sharp edges), and vehicle identification (VIN visible).
How long does an MOT take?
A standard MOT test takes approximately 45 minutes to one hour. If the tester needs to spend additional time on borderline items or if the vehicle has a large number of advisory items, it may run longer. Allow an hour as a rule of thumb.
What is the difference between a dangerous failure and a major failure?
A dangerous failure means the vehicle poses an immediate road safety risk — it must not be driven. A major failure means the vehicle has a significant fault that must be repaired before it can be used on the road. Both cause the MOT to fail. A minor failure does not fail the test but must be monitored.
Can I drive a car to an MOT test with no current MOT?
Yes — this is the one exception. You can drive a vehicle directly to a pre-booked MOT test appointment even if the MOT has expired. You cannot make any other journeys. If the car fails the test, you must not drive it away unless the tester confirms it is safe to do so for the specific repair needed.
What is an advisory on an MOT?
An advisory is a note from the MOT tester flagging an item that is not yet a failure but may become one. Advisories are recorded in the MOT history and are visible on DVSA records. Repeated advisories for the same item suggest a developing problem that the seller has not addressed.
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