MOT Failure Reasons Explained
The most common MOT failures involve lights, tyres, brakes, windscreen damage, wipers, suspension, steering, emissions and registration plates. Checking these areas before the test may help you find simple problems early.
At HON CAR SERVICE, we can help arrange MOT testing, pre-MOT inspections, servicing and repairs in and around Southampton.
What is an MOT failure?
An MOT failure means the tester has recorded one or more major or dangerous defects, or another item that does not meet the required standard. Minor defects and advisories may be recorded without causing a failure.
The MOT checks the vehicle’s condition on the day of the test. It is not a complete mechanical service or a guarantee of future reliability.
Common MOT failure reasons
1. Lighting and signalling defects
- Failed headlights, brake lights or indicators
- Incorrect headlight alignment
- Damaged or insecure lamp units
- Incorrect colour or visibility
2. Tyres and wheels
- Tread below the legal minimum
- Cuts, bulges, cracks or exposed cords
- Incorrectly fitted or insecure tyres
- Severe or uneven wear
3. Brake problems
- Insufficient or uneven braking force
- Worn pads or discs
- Brake-fluid leaks
- Parking-brake problems
- Brake warning-light faults
Grinding, a soft pedal or reduced stopping performance should be checked before the MOT.
4. Windscreen, wipers and washers
- Cracks or chips affecting the driver’s view
- Wipers that do not clear the required area
- Damaged blades
- Non-working washer jets or insufficient screenwash
5. Steering and suspension
- Excessive play in steering components
- Damaged or leaking suspension parts
- Broken springs
- Unusual movement or unsafe handling
6. Exhaust and emissions
- Excessive smoke
- Exhaust leaks or insecure components
- Emissions above the applicable limit
- Missing or damaged emissions equipment where relevant
7. Bodywork, doors and structure
- Dangerous sharp edges
- Serious corrosion near structural or safety areas
- Doors that do not latch securely
- Loose body panels or unsafe components
8. Seatbelts and seats
- Belts that do not lock, release or retract correctly
- Damaged belt webbing
- Insecure seats or mounting points
9. Registration plates and VIN
- Unreadable or insecure registration plates
- Incorrect display or damaged characters
- A VIN that is missing or cannot be identified where required
How to reduce the risk of an MOT failure
- Check all lights and replace failed bulbs.
- Inspect tyre tread, pressure and sidewalls.
- Test the brakes and investigate unusual noises.
- Clean the windscreen and replace damaged wipers.
- Top up screenwash and check the washer jets.
- Look for warning lights, smoke, leaks or unusual noises.
- Arrange a pre-MOT inspection if you are unsure.
A pre-MOT inspection can identify potential faults, but it cannot guarantee an MOT pass.
What happens after an MOT failure?
The tester will provide a certificate showing the recorded defects. The repair process depends on the type and seriousness of each item.
- Dangerous: the vehicle should not be driven until repaired.
- Major: repairs are required and driving may be restricted.
- Minor: the issue is recorded and should be repaired as soon as practical.
- Advisory: the item is not an immediate failure but may need monitoring.
Follow the tester’s instructions and do not drive if the vehicle is unsafe.
Frequently asked questions
What is the most common MOT failure?
Lighting, tyre, brake, windscreen and wiper problems are common, but failure patterns vary between vehicles.
Can I repair an MOT failure myself?
Simple items may be suitable for a competent owner, but safety-critical or complex faults should be inspected and repaired professionally.
Can an MOT failure be appealed?
There is an official appeal process. Follow the current GOV.UK guidance and do not authorise repairs before understanding the appeal requirements.
Does an MOT failure cancel the old certificate?
The answer depends on the defects and the circumstances. Check the MOT certificate and official guidance before driving.
Book an MOT or pre-MOT inspection
HON CAR SERVICE can help arrange MOT testing, pre-MOT inspections, servicing and repairs for many makes and models. Visit our MOT and service options or start an online quote using your registration and postcode.