Everything an MOT checks, area by area.
A Class 4 MOT works through a set list of areas defined by the DVSA, from the brakes and steering to the lights, tyres, screen and emissions. The tester checks each one against the minimum legal standard, the same inspection whatever garage you use, because the standard is set nationally.
Here is what actually gets checked in each area, why cars most often fail there, and the things an MOT does not cover.
The areas a tester works through.
The whole test is grouped into these areas. Each one is checked against the legal minimum and the result recorded as a pass, or a fault graded Minor, Major or Dangerous.
Steering & Suspension
- Steering control & system
- Power steering
- Suspension, wheel bearings & driveshafts
- Shock absorbers
Brakes
- Parking brake & service brake
- Anti-lock braking system
- Mechanical & hydraulic components
- Brake performance & balance
Wheels & Tyres
- Tyre condition, tread depth & type
- Wheel condition & security
- Tyre pressure (visual)
- Spare wheel carrier, where fitted
Lighting
- Position & rear lamps
- Headlamps & headlamp aim
- Direction indicators & hazards
- Rear reflectors
Visibility
- Windscreen condition & wiper sweep
- Washer bottle & screenwash
- Mirrors
- Horn
Body, Fuel & Structure
- Vehicle identification number & plate
- Doors, boot & bonnet security
- Seats, seatbelts & airbags (SRS)
- Fuel system, fuel cap & leaks
- Exhaust system & emissions
What the tester actually looks at.
Each area is more than one check. Here is what sits inside it, how the tester judges it, and the everyday things that catch cars out. Most are small, and a lot of them are worth a two-minute look the night before.
If anything does fail, we explain exactly what and why, in plain terms, and tell you what it takes to put right.
Brakes
Braking is measured, not just looked at. The car goes onto a roller brake tester (or is checked with a decelerometer) so the tester can see how much stopping force each wheel produces and how evenly it is shared side to side.
- Service (foot) brake efficiency and overall performance
- Parking (hand) brake holding ability
- Braking balance across each axle, left to right
- Brake pedal and lever condition and travel
- Discs, drums, pads, shoes, hoses and pipes for wear, damage or leaks
- Anti-lock braking (ABS) warning light, where fitted
Brakes that are worn, pulling to one side or simply not stopping the car efficiently enough are common fails, along with a handbrake that will not hold, a corroded or leaking brake pipe, or an ABS warning light that stays lit.
Steering & suspension
The tester checks how tight and true the steering is and how the car sits on its suspension, both by feel at the wheel and with the car raised so the joints and mountings can be inspected and moved.
- Steering wheel, column and any play in the system
- Power steering operation, fluid and warning light
- Track rod ends, ball joints and wheel bearings
- Springs, shock absorbers and how the car settles
- Driveshaft joints and gaiters (CV boots)
- Suspension mountings and bushes for wear or damage
Excessive play in a joint, a worn or leaking shock absorber, a split CV gaiter, a broken coil spring, or a power-steering fault light are the usual culprits here.
Wheels & tyres
Every tyre is checked for depth, condition and the right type, and the wheels for damage and security. The legal minimum tread is 1.6mm, across the central three-quarters of the tyre and right around it.
- Tread depth of at least 1.6mm across the central three-quarters
- Cuts, lumps, bulges or exposed cords in the tyre
- Correct tyre size, type and speed rating, matched across an axle
- Wheel condition and security
- Tyre valve condition (a visual check)
Tread below 1.6mm is the classic fail, along with a cut, bulge or perished sidewall, mismatched or wrong-rated tyres on the same axle, or a wheel that is damaged or not secure.
Lights & signalling
Lighting and signalling faults are among the most common reasons cars fail, and they are usually the cheapest to put right. The tester works round every lamp for condition, operation, colour and aim.
- Headlamp condition, operation and aim
- Side, rear, brake and number-plate lights
- Indicators and hazard warning lights
- Rear reflectors and, where fitted, fog and levelling lights
- Headlamp washers or levelling, where the car has them
A blown bulb, a misaligned headlamp, a cracked lens letting water in, or a brake light or number-plate light that has stopped working will all fail the test, and all of them are worth checking the night before.
Visibility (the driver’s view)
The test protects your view of the road. Damage is judged by where it sits: a chip larger than 10mm directly in the driver’s line of sight, or larger than 40mm anywhere else the wipers clear, will fail.
- Windscreen condition, judged by the 10mm / 40mm zones
- Wiper blades that sweep the screen clean
- Washers working, with screenwash actually in the bottle
- Mirrors present, secure and undamaged
- Anything obstructing the driver’s view
A chip or crack too big in the driver’s eyeline, split or worn wiper blades, an empty washer bottle on its own, or a missing or cracked required mirror are all straightforward fails here.
Seatbelts, airbags & interior
Every belt is checked as a safety-critical item, along with the airbag system and the parts of the interior the test covers. The tester tugs each belt to check it locks and looks over the webbing and buckle.
- All seatbelts present, secure and in good condition
- Belts that lock when tugged sharply, and buckles that latch
- Airbag (SRS) system and its warning light, where fitted
- Driver’s seat security and adjustment
- Doors that open, close and stay latched; boot and bonnet secure
- A horn that sounds with one press
A frayed or non-locking belt, an airbag warning light that stays on, an insecure seat, a door that will not stay shut, or a horn that does not work are the common fails in this area.
Body, structure, fuel & emissions
Finally the tester checks the shell, the fuel system and the emissions. Structure is inspected for corrosion in prescribed areas around load-bearing points, and the exhaust for security, completeness and what comes out of it.
- Vehicle identification number and a correctly spaced, legible number plate
- Structural condition and corrosion in prescribed areas
- Fuel system secure, with no leaks, and a sealing fuel cap
- Exhaust secure and complete, with no major leaks
- Emissions within the limits set for your vehicle (petrol or diesel)
Excessive corrosion in a structural area, a leaking or insecure exhaust, emissions over the limit, a removed or tampered diesel particulate filter, or an incorrectly spaced or unreadable number plate will all fail.
Pass, or a fault graded three ways.
Anything the tester finds is recorded against the same national scale, so a result means the same thing wherever the car is tested.
Noted for you to keep an eye on. The car still passes, but it is worth putting right before it turns into something bigger.
A fail. It has to be repaired and the car retested before a pass certificate can be issued.
A fail, and the car is not safe to drive until it is fixed, not even to another garage. Best recovered rather than driven.
What an MOT does not check.
An MOT is a pass or fail snapshot of whether the car meets the legal minimum on the day of the test. It is not a health check, and it is not a promise the car will not develop a fault tomorrow. It does not cover:
- The condition of the engine, clutch and gearbox
- Oil, coolant and other fluid levels or quality
- General wear and tear that is not a listed safety item
- Whether the car will stay reliable until its next test
That is what a service is for. Most cars need both. One keeps you legal, the other keeps the car in good all-round condition, which is why you can book them together and add the MOT for just +£39.99.
Ready to book your MOT?
A fixed £49.99 for a Class 4, done while you wait, with everything above checked to the DVSA standard and explained in plain terms.
All prices include VAT. MOTs are zero-rated, so there is no VAT on an MOT.