Pre-MOT Checklist: 15 Things to Check Before Your MOT Test

Around 40% of vehicles fail their MOT on the first attempt. Many of these failures are for simple issues you can check yourself. Use this checklist before your MOT to catch problems early and increase your chances of passing first time.

The good news is that a significant proportion of these failures could be avoided with a 20-to-30-minute check at home. By working through each category below, you will cover the areas that account for the vast majority of MOT failures across the UK. Whether your car is three years old and facing its first test or a 15-year-old veteran, this checklist applies equally.

Looking for your specific car? Check MOT failure rates by make and model for detailed data on 400+ vehicles.

Lights and Signals

1. Headlights: Check both dipped and main beam work. Look for cracks, chips, or condensation in the lens. Condensation inside the headlight unit does not automatically fail, but if it is heavy enough to obscure the beam pattern, it will. On older vehicles, check that the headlight aim has not shifted — testers use a beam aligner, and misaligned headlights are a common fail.
2. Brake lights: Ask someone to press the brake pedal while you check all brake lights illuminate. This includes the high-level brake light if your vehicle is fitted with one. Make sure each light comes on promptly and at full brightness.
3. Indicators: Test all four indicators and hazard lights. They should flash at the correct rate — a rapid flash usually indicates a blown bulb elsewhere in the circuit. Check that the indicator lenses are not cracked or missing.
4. Rear lights and number plate light: Ensure all rear lights work and the number plate is clearly illuminated. The number plate light is one of the most overlooked items and is a frequent cause of failure, particularly on hatchbacks and estate cars where the boot-mounted light can be easily damaged.

Tyres and Wheels

5. Tread depth: Legal minimum is 1.6mm across the central three-quarters. Use a 20p coin — if you can see the outer band, tyres may be illegal. Check the tread depth at several points around each tyre, as uneven wear can mean one section is below the limit while another appears fine.
6. Tyre condition: Check for cuts, bulges, or cracks in the sidewall. These are automatic failures. Run your hand along the inner sidewall as well, since damage here is easy to miss visually. Also check that both tyres on the same axle are the same type (radial or cross-ply) — mixing types on the same axle is an MOT failure.
7. Tyre pressure: While not tested directly, incorrect pressure affects handling and wear patterns. Under-inflated tyres wear on the edges and can cause the vehicle to pull to one side, while over-inflation causes centre-tread wear. Check pressures when the tyres are cold, using the manufacturer's recommended figures (usually found inside the driver's door frame or in the owner's manual).

Visibility

8. Windscreen: Check for chips or cracks. Damage larger than 10mm in the driver's view (Zone A — a 290mm-wide strip centred on the steering wheel) or 40mm elsewhere in the swept area will fail. Small chips outside the driver's direct view are usually acceptable, but get them repaired early before they spread in cold weather.
9. Wipers: Blades should clear the screen without smearing or juddering. Replace if worn. Wiper blades deteriorate over time even when not in use, so replace them at least once a year. Check that the wiper arms have not become loose or bent, which can cause uneven pressure across the blade.
10. Washer fluid: Top up the washer bottle. The system must work during the test. The tester will check that the washers deliver fluid to the windscreen and that the wipers then clear it effectively. Use a proper screenwash additive rather than plain water, especially in colder months, to prevent the system freezing.
11. Mirrors: All mirrors must be present, secure, and provide adequate rear view. The interior mirror and both door mirrors will be checked. Cracked mirror glass is not an automatic failure, but if it distorts the view significantly, it may be. Loose or wobbly mirror housings are a common advisory that can become a failure.

Under the Bonnet

12. Oil level: Check and top up if needed. Low oil can cause engine warning lights, and if the engine management light is illuminated on the dashboard, your vehicle will receive at least an advisory. On diesel vehicles, particularly, low oil can affect the diesel particulate filter (DPF) regeneration process.
13. Brake fluid: Should be between min and max marks. If low, there may be a leak or worn pads. Dark or discoloured brake fluid may indicate it needs replacing, though this is not directly tested in the MOT. However, degraded brake fluid can lead to poor braking performance, which is tested.
14. Horn: Must be loud enough to warn other road users. Press the horn and listen — it should produce a clear, continuous tone. Horns that sound weak or intermittent will fail. On some cars, particularly those exposed to damp conditions, the horn can corrode and lose effectiveness over time.

Safety Equipment

15. Seatbelts: Check all belts for damage, that they retract properly, and buckles click securely. Pull each belt out fully and inspect for fraying, cuts, or twisting. The buckle should release cleanly when the button is pressed. Test the inertia reel by giving the belt a sharp tug — it should lock immediately. Seatbelt failures account for around 3% of all MOT failures, and many are caused by buckles clogged with debris from children's snacks or general dirt.

Digital Checklist

While a physical walk-around is essential, digital tools can add another layer of preparation. AutoSafe's free MOT prediction tool analyses your vehicle's make, model, age, mileage, and full MOT history to identify its specific weak points. Rather than checking a generic list, you can focus your attention on the components that are statistically most likely to cause your particular vehicle to fail.

For example, if AutoSafe identifies that your 2016 Vauxhall Corsa has a high risk of suspension failure, you know to pay particular attention to any knocking sounds or uneven tyre wear before booking your MOT. This targeted approach is far more efficient than a blanket inspection, though we still recommend working through the full 15-point checklist above regardless.

The tool also shows your vehicle's full MOT history, including all previous advisories. Advisories from your last MOT are the single best predictor of what might fail next time, so reviewing them before your test is one of the most valuable things you can do.

What Testers Look For (That You Might Miss)

The official MOT test covers far more than the 15 items above. Here are additional areas that testers examine which motorists frequently overlook:

• Exhaust emissions: Your vehicle's exhaust emissions are measured during the test. Diesel vehicles are checked for smoke opacity, while petrol vehicles have their CO and hydrocarbon levels measured. A 20-minute motorway drive before the test helps the catalytic converter and DPF reach optimal operating temperature, significantly improving your chances of passing. Vehicles with a DPF that has been removed or tampered with will receive an automatic major failure.
• Seat condition: The driver's seat must be securely mounted and the backrest must lock in the upright position. Testers will check for excessive movement in the seat runners and ensure the adjustment mechanism works. This is particularly worth checking on high-mileage vehicles where the seat rails can wear.
• Registration plates: Both front and rear plates must be present, legible, and conform to the correct format. Faded, cracked, or illegally spaced plates will fail. Number plate fixings should be secure — plates held on with adhesive pads that are peeling away are a common issue.
• Fuel cap: The fuel filler cap must seal properly to prevent fuel vapour escaping. A damaged or missing seal on the fuel cap is a straightforward failure that costs very little to fix but catches many motorists off guard.
• Doors and boot: All doors must open and close securely from both inside and outside. The bonnet catch must hold the bonnet closed while driving. Boot and tailgate latches are also checked.
• Exhaust system: Beyond emissions, the physical condition of the exhaust is examined. Holes, excessive corrosion, and insecure mountings are all failure points. Listen for blowing or rattling sounds underneath the car, particularly when the engine is running.
• Fluid leaks: Significant fluid leaks (oil, coolant, brake fluid) are MOT failures if they pose a risk. Check your usual parking spot for puddles or stains underneath the vehicle.

Common DIY Fixes Before Your MOT

Many of the most common MOT failures can be fixed at home with basic tools and minimal cost. Here are the easiest wins:

• Bulb replacement: A blown bulb is the single most common reason for MOT failure, yet replacing one typically costs between two and eight pounds and takes five to fifteen minutes. Most modern cars allow bulb access from behind the headlight unit under the bonnet. Carry spare bulbs in your glovebox so you can replace them as soon as you notice a failure. If you are unsure about the bulb type, your owner's manual or any motor factor will be able to advise.
• Wiper blades: Worn or split wiper blades are an easy replacement. New blades cost between eight and fifteen pounds per pair from any motor factor or supermarket. They clip or slide onto the wiper arm and take less than five minutes to fit. Test them with the washer fluid to make sure they clear the screen cleanly.
• Washer fluid: Topping up screenwash costs a couple of pounds and takes thirty seconds. If the washer jets are blocked, a pin or needle can clear them. Adjust the jet aim so fluid hits the centre of the windscreen.
• Tyre pressure: Use a tyre pressure gauge or a free airline at a petrol station. Correct pressure improves handling, fuel economy, and tyre life. Check your pressures when the tyres are cold for an accurate reading.
• Number plate bulbs: Often overlooked, number plate bulbs are cheap (under two pounds) and usually accessible by removing a small lens cover with a screwdriver. This is one of the quickest fixes you can make.
• Registration plate condition: If your plates are faded or cracked, replacement plates cost around fifteen to twenty pounds per pair from a registered number plate supplier. You will need your V5C document as proof of entitlement.

What Happens If You Fail?

If your car fails its MOT, don't panic. You have several options depending on the severity of the defects found:

• Get repairs done at the testing centre: Many MOT centres also offer repairs. If you have the work done on site, you can request a partial retest that only covers the failed items. This is often the quickest and most convenient option.
• Take it elsewhere for repairs: You can have repairs done at a different garage and return to the original testing centre within 10 working days for a free partial retest. This only applies if the vehicle is returned to the same testing station that conducted the original test.
• Full retest: If you return after 10 working days, or go to a different testing station, you will need to pay for a full retest. The maximum fee for a full retest is the same as the original MOT fee.

Understanding defect categories: Since May 2018, MOT defects are classified into three categories:

• Minor defects: Issues that do not affect the vehicle's safety or environmental impact significantly. The vehicle passes with advisories noted on the certificate. No repair is legally required, but it is recommended.
• Major defects: Problems that may affect safety, put other road users at risk, or have an impact on the environment. The vehicle fails and must be repaired. You may still drive the car if your previous MOT certificate has not expired.
• Dangerous defects: Serious issues that pose a direct and immediate risk. The vehicle fails and must not be driven on public roads until the defect is rectified. Driving a vehicle with a dangerous defect is a criminal offence.

Partial retest rules: A partial retest covers only the items that failed. If you leave the vehicle at the testing station overnight and collect it the next day after repairs, the partial retest is free. If you drive the vehicle away and bring it back within 10 working days, the partial retest is also free at the original station, but the tester may re-examine items that could have been affected by driving the vehicle (such as brakes or tyres). After 10 working days, you will need a full retest.

The best approach is prevention. Use AutoSafe to identify your vehicle's weak points before booking your MOT, so you can address issues proactively. Drivers who fix known advisories and risk areas before their test save an average of 30-50% on total repair costs compared to those who only discover problems at the testing station.

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