The DVSA’s own data is consistent year after year: a substantial portion of MOT failures are for things the driver could have spotted and fixed before the test. Bulbs, tyre tread, wipers, screenwash — none of these require mechanical knowledge or specialist tools. They require five minutes and a working torch.
This is a six-check walkaround. Each check takes about five minutes and targets a cluster of RFRs that sit near the top of the national failure list. Do all six and you’ll have addressed the bulk of the avoidable failures before the car ever rolls onto the ramp.
You need: a torch, a 20p coin, and a friend willing to sit in the driver’s seat and press things on command.
Check 1: All eight lamps (5 minutes)
Walk around the car with the ignition on. You’re checking:
- Both dipped headlamps
- Both main-beam headlamps
- Both rear tail lamps
- Both rear brake lights (ask your friend to hold the pedal)
- Both front and rear fog lamps
- Both number-plate lamps (often forgotten — they sit in the boot lid or bumper trim)
- Both direction indicators, front and rear, and the side repeaters if fitted
This covers RFR 5.2.1 (headlamp aim and function), RFR 5.2.5 (stop lamps), and RFR 5.2.6 (number-plate lamp). A failed number-plate bulb is one of the more embarrassing Major defects, given the fix costs less than a coffee.
While you’re there, check the indicator rate. Indicators that flash too fast — a sign of a failed bulb on the same circuit — are also a fail. Press the hazard switch and walk around to confirm all four corners blink in unison at roughly 1 to 2 flashes per second.
If a lamp is out, most bulbs on a modern car are owner-replaceable. Check the handbook first; some LED clusters on newer vehicles require a garage. But on anything more than five years old, a twist-and-pull bulb holder is more likely than a sealed unit.
Check 2: Tyres — tread, sidewalls, and inflation (5 minutes)
Tyre tread is the single most common MOT failure category. The legal minimum is 1.6mm across the central three-quarters of the tread band, all the way around the circumference. That’s a thin margin.
The 20p coin test: insert a 20p piece into the main tread groove. If the outer band of the coin is visible above the groove, the tread is at or below 1.6mm — and that’s a Major under RFR 31194. If cord is visible through the rubber anywhere, expect a Dangerous rating.
Check all four tyres, including the spare if your car still has one (the MOT doesn’t test the spare, but it’s good practice).
Sidewalls are worth a look too — bulges, cuts, or cracking in the rubber wall are separate failures from tread depth. A bulge means the inner structure has failed and the tyre is at risk of sudden deflation. RFR 31189 covers this and it’s not a borderline call.
Inflation: an over- or under-inflated tyre won’t itself fail the test, but it will cause uneven wear that makes the tread depth harder to read and can affect the brake and steering checks. Inflate to the manufacturer’s figure (usually on a sticker inside the driver’s door or in the handbook) before the test.
Check 3: Wipers, screenwash, and windscreen (5 minutes)
Turn the wipers on and run them through a full cycle. The blade needs to clear a wide, streak-free arc across the primary vision zone — the area directly in front of the driver. A blade that chatters, leaves a strip uncleared, or smears rain across the screen rather than shifting it covers RFR 8.1.4.
Lift the blades and look at the rubber edge. If it’s cracked, torn, or the rubber has separated from the frame, replace the blade. It’s a £10 job at any motor factor and takes about two minutes.
Screenwash: the tester will operate the washer. If the reservoir is empty, that’s an advisory rather than a fail — but it’s a pointless one to collect. Fill it before you go.
Windscreen: cracks and chips in the driver’s primary vision zone are assessed under RFR 8.1.2. A chip of 10mm or more in Zone A (the 290mm band directly in front of the driver) is a Major. A crack anywhere in the swept area that impairs vision can be Dangerous. If you have a chip that you’ve been meaning to get repaired, do it before the test. Most insurance policies cover chip repair at no excess, and a filled chip won’t grow.
Check 4: Brake fluid and handbrake travel (5 minutes)
Open the bonnet and find the brake fluid reservoir. The level should sit between the MIN and MAX markers. A low level could indicate wear in the pads or discs (as pads wear, more fluid is needed to fill the caliper space) or a slow leak somewhere in the circuit. A tester won’t fail you on the fluid level alone, but it’s a useful indicator of underlying brake condition.
The handbrake is tested on a rolling road or brake plate: the tester checks that the car holds under a defined force. Before the test, pull the handbrake up firmly and count the clicks. Most manufacturers specify 4 to 8 clicks for a correctly adjusted handbrake. More than that suggests the cable needs tightening. The fix is usually minor, but if the rear brakes have been done recently and the cable was disturbed, it’s worth checking.
If the brake pedal travels a long way before you feel resistance — further than it did six months ago — that’s worth investigating before the test, not after.
Check 5: Seatbelts, horn, and boot (5 minutes)
Pull each seatbelt fully out and look at the webbing. Fraying, cuts, or a belt that won’t retract are all fail items under RFR 3.6. The buckle needs to engage and release cleanly. Sit in each seat and test the inertia reel: pull the belt out sharply — it should lock. A belt that doesn’t lock on a sharp pull will fail.
The horn is a single-item check: press it, confirm it makes a continuous sound, and confirm the sound is from the front of the vehicle. It’s easy to overlook because it works fine until it doesn’t.
Boot and rear doors: make sure the boot closes and latches securely. A boot that can’t be latched (failed mechanism, broken lock) is assessed as a structural/bodywork item and can affect the result. Also check that any number-plate fitted to the boot lid is secure, correctly lit (covered above), and readable.
Check 6: Under-bonnet visual and suspension bounce (5 minutes)
You don’t need to know what every component is. You’re looking for obvious fluid leaks on the engine bay floor, cracked or split hoses, and any warning lights on the dashboard that might point to an emissions or electrical issue.
The engine management light (EML) is a direct fail under RFR 9.3.4 if it illuminates with the ignition on. An EML doesn’t mean the engine is about to stop — it means a sensor has logged a fault code. Get the code read (any motor factor will do it for free with an OBD reader) before the test so you know what you’re dealing with.
Suspension bounce test: place both hands on each corner of the car and push down firmly, then release. The car should rise, settle, and stop. If it bounces up and down more than twice before stopping, the dampers are worn. A tester will check play in the suspension components on the ramp, but badly worn dampers can affect the brake test result as well as attracting a suspension defect.
If something shows up
A walkaround like this will occasionally reveal something beyond a bulb or a wiper blade — a tyre that needs replacing, a crack in the screen, a seatbelt that’s worn through. In those cases, you’ve done yourself a service by finding it before the tester did.
For anything that needs repair, the MOT cost estimator at /tools/mot-cost-estimator/ is a useful starting point for understanding the typical range across UK centres. You can then decide whether to sort it before the test or book the test and factor the cost in.
The walkaround won’t catch everything. Brake efficiency, suspension play, and emissions all need ramp equipment and instruments that you don’t have on your driveway. But the checks above cover the most common reasons for rejection, and none of them cost anything to do.