How to prepare for your MOT: a 10-minute DIY checklist
18 July 2026·6 min read
The light check that catches most cars out
Lamps are the most common MOT failure in Britain, and the bulb that does it is often the one you never see. Brake lights and number-plate lights only show up when someone stands behind the car, so a two-person check before you book saves money.
Check them all: headlights on main and dipped, indicators, brake lights, reversing light, number-plate lights, fog lights and sidelights. A bulb costs a few pounds and takes minutes at home. The same bulb on test day comes with a labour charge.
Tyres, brakes and the stuff underneath
Look at tread depth on each tyre. You need at least 1.6mm across the central three-quarters in a continuous band, with no cuts, bulges or exposed cords. If the car has a spare or space-saver, that needs to be in good order too.
Listen for brake judder or a pedal that sinks before you book. A brake issue you find at home costs less than the same issue found at the test, because you can choose where the work is done.
- Wipers and washers: fit new blades if they smear, top up fluid
- Horn: one short blast before you go in
- Exhaust: a loud rumble or smoke at idle is worth fixing first
- Mirrors: cracked glass or a loose housing fails
- Warning lamps: an engine management or ABS light on fails the car before the test starts
Presentation, paperwork and the emissions run
The MOT is digital, so you do not need to bring paperwork, but the plates still need to be clean, legible and undamaged. A faded or cracked plate fails. A dirty one often fails in practice, and it takes two minutes to clean.
Diesels and older petrols struggle on a cold catalyst. Drive for 15 to 20 minutes before you arrive so the engine is at operating temperature. It is the cheapest way to help the emissions result.