Understanding what happens during your MOT test takes away much of the worry and helps you prepare properly. This guide walks you through what testers check and how to get your car ready.
The MOT test is a legal requirement for all vehicles over three years old in the UK. Without a valid MOT certificate, you cannot legally drive on public roads, and your insurance may not be valid.
What Gets Tested During an MOT
The MOT test covers eight main areas. Here’s what testers look at:
Lights and Electrical Systems – All lights must work properly, including headlights, brake lights, indicators, hazard lights, fog lights, and number plate lights. Testers check that lenses aren’t cracked and lights are secure. Your horn must work too.
Brakes – Testers check brake pads, discs, and drums for wear and damage. They measure brake performance using a roller brake tester. Your service brake must be at least 50% efficient, whilst your handbrake must be at least 16% efficient. Faulty brakes are a common MOT failure, so get them checked if you notice any problems.
Steering and Suspension – Testers check your steering wheel for excessive play and examine all steering components. Your suspension gets tested for worn shock absorbers, broken springs, and loose parts.
Tyres and Wheels – Each tyre must have at least 1.6mm of tread depth. Testers look for cuts, bulges, or cracks and check your tyres are properly inflated. Wheels must not be damaged or bent.
Body and Structure – Your car’s body gets examined for rust or damage that could affect safety, especially around seat belt mountings and suspension points. The exhaust system is checked for leaks and security.
Windscreen and Windows – Your windscreen must be clear of cracks or chips in the driver’s line of sight. A chip bigger than 10mm in the wiper area will cause a failure. Wipers must clean the screen properly without streaking.
Emissions – Petrol cars get their exhaust emissions checked with a gas analyser. Diesel cars go through a smoke test. Cars that produce too much pollution will fail.
Seat Belts and Airbags – All seat belts must click into place securely and release properly. Testers check for fraying or damage. Airbag warning lights must work correctly.
Understanding MOT Defects
MOT testers classify problems into three categories:
Minor Defects – Small problems that don’t affect safety. Your car passes with minor defects, but they’re noted on your certificate.
Major Defects – Problems that could affect safety or the environment. Your car fails if it has major defects. Common examples include worn brake pads, tyres below legal tread depth, or broken headlights.
Dangerous Defects – Serious problems that pose immediate safety risks. You must not drive your car until these are fixed. Examples include seriously worn brakes or tyres with dangerous damage.
MOT Test Checklist
Do these simple checks before your test:
| Check Area | What to Look For | How to Check |
| Lights | All bulbs working, lenses not cracked | Walk around car with lights on, ask someone to help with brake lights |
| Tyres | Tread depth at least 1.6mm, no damage | Use 20p coin test in tread grooves |
| Windscreen | No chips over 10mm, no cracks | Look carefully at windscreen |
| Wipers | Clean screen without streaking | Turn on wipers and washers |
| Brakes | No squealing, car stops straight | Test gently on quiet road |
| Number Plates | Clean and readable | Check all numbers and letters are clear |
| Warning Lights | Work as they should | Turn on ignition and check lights |
| Seat Belts | Click and release properly | Test each belt |
Common Reasons Cars Fail
These are the most frequent failure points at our MOT testing centre:
Lighting problems are the number one reason for failures. Blown bulbs, cracked lenses, or lights that don’t work properly are usually quick and inexpensive to fix.
Tyre issues cause many failures. This includes tread depth below 1.6mm, cuts, bulges, or damage. Check your tyres regularly and replace them when they get close to the legal limit.
Brake problems are serious safety issues. Worn brake pads, damaged discs, or brake fluid leaks must be fixed. If you hear squealing or grinding when you brake, get them checked straight away.
Windscreen damage in the driver’s line of sight will fail your test. Get chips repaired quickly before they spread.
Emissions failures happen when cars produce too much pollution. Regular servicing helps keep your engine running cleanly.
How to Prepare Your Car
Book your test at least a month before your current certificate expires. This gives you time to fix any problems.
Clean your car before the test. Testers need to see things clearly. Make sure number plates are readable and remove clutter from inside.
Check all fluid levels, including engine oil, brake fluid, coolant, and screen wash. Look under your car for any leaks.
Test all your lights and replace any blown bulbs. Check your windscreen wipers work properly.
If you notice any problems with brakes, steering, or other important systems, get them checked before your MOT.
What Happens If You Fail
If your car fails, you’ll receive a refusal notice listing all problems found. You cannot legally drive without a valid MOT certificate, except to a garage for repairs or to a pre-booked retest.
You have 10 working days to get problems fixed and return for a partial retest. The tester only checks the items that failed. Many garages offer free or reduced-price partial retests if you get the work done with them.
Getting Your MOT in East Ham
The official MOT inspection manual from the Driver and Vehicle Standards Agency sets out exactly what testers must check.
Book your MOT at our DVSA-approved centre in East Ham. We explain any problems we find and give you honest advice about repairs. Our goal is to help keep you safe on the road whilst making the MOT process as straightforward as possible.
