What's checked on an MOT?

Your vehicle is due for an MOT once a year, and while many of us just drop it off with our nearest garage, you might want to know exactly what they're going to be looking for. We've put together a list of everything that's checked, according to the government's own guidelines.

It's important to note that many of these are covered if you find the right car insurance policy, or can be fixed quite cheaply yourself, so it pays to run through a pre-MOT checklist to get yourself ready for your test.

In This Guide:

• Lights
• Body and vehicle structure
• Basic features and components
• Battery
• Wiring
• Towbars
• Exhaust system and emissions
• Tyres and wheels
• Registration plate
• What an MOT doesn't cover

Lights

Your vehicle's front, rear, brake, fog, indicator and registration plate lights will all be checked, and they must not only be working and clear but also correctly positioned. They can't be obscured by any deflectors or bodywork damage. They'll have to work with a single operation of the switch.

Additionally, they'll need to be the correct colours and match up, so if one of your headlights has a slightly blueish tinge the other shouldn't be clear white.

Body and vehicle structure

Your vehicle will be inspected for any signs of excessive corrosion or dangerous sharp edges that could cause damage or injury. The examiner will check all around the bodywork of your vehicle including the chassis, engine mountings, seats, bonnet, boot and doors to confirm it's all safe and secure.

The doors will come under scrutiny; they will have to have a secure and working latch, hinges and catches that are secure and an opening mechanism which allows them to be opened from both inside and outside the vehicle (in the case of front doors) and at least from outside the vehicle (in the case of rear doors, the bonnet and the boot).

They'll also check your windscreen, mirrors and wipers for any signs of damage that could obstruct the driver's view. There must not be any damage larger than 10mm within the area cleared by the driver's side wiper, and no damage or other obstruction larger than 40mm within the rest of the swept area. The mirrors must be securely fastened and provide an adequate view of the road.

The VIN will be listed on vehicles first used on or after 1 August 1980. Your car will be inspected to check that a single VIN is displayed, except on multistage build vehicles, for example a van conversion.

Basic features and components

Inside the car, your vehicle's seatbelts must be of an appropriate length and in good working order. This means that they'll fit around the majority of people and will tighten to fit. They must also lock into place in the event of sharp braking, to prevent injuries.

Your speedometer must also be operational and able to be illuminated, and the examiner will check that it's visible and that the speed can be read.

The examiner will check that the steering wheel in your vehicle is in good condition and working order. So it will need to turn unhindered in both directions and not have any damage to the components. They'll also check the power steering fluid level if applicable, which will need to be above the minimum level in the reservoir. Any steering lock your vehicle has will need to operate only when the engine isn't running.

The horn will be checked, to make sure it emits a single continuous note that's loud enough to be heard by other road users.

Battery

Your battery ill be checked by the examiner to make sure it is securely fastened inside the car. Obviously it will need to be operational in order to start the vehicle for the emissions test, but it must also be undamaged and free of any leaks.

Wiring

The wiring inside your vehicle will be checked, to ensure it's up to standard. This means without damage and secured to the bodywork rather than hanging loose in a position that could cause an electrical fault or for it to catch in any moving parts.

Towbars

Your examiner will check the towbar on a few different aspects. Firstly that it is correctly secured and in good condition, especially if it is an after-market part that was fitted later.

Also they'll check the electrical socket attached to the towbar to ensure it's in sound working condition, and that it correctly operates all parking, brake, fog and indicator lights on a trailer.

Exhaust system and emissions

The examiner will check that your exhaust system is free of any leaks or damage. This can occur due to corrosion so it's quite common for this to accumulate in older cars. If your car was fitted with a catalytic converter it needs to still be present.

In terms of emissions, your vehicle will need to fall within the legal limit, based on it's age and the type of vehicle. The examiner will use a gas analyser to test these emissions while the car is running, while also checking that the smoke emitted isn't too excessive or colourful that it could obscure your own or other drivers vision on the road. 

Because the examiner will test your emissions it's essential that you have sufficient engine oil and fuel in your car at the time of service to carry out the emission checks.

Tyres and wheels

The tyres will be scrupulously checked by your examiner for damage, wear or bulging. You'll need to have more than 1.6mm of tread depth across the centre 75% of every tyre. Also there must be no cuts in excess of 25mm, bulges, lumps, tears or exposure of the inner cord. 

Additionally the wheels will have to be in good condition, without damage that could impair the tyre or cause damage or injury, and all the wheel nuts must be in place and secured fast.

Registration plate

The examiner will check that a registration plate is fitted at the front and rear of the vehicle. These plates need to be secure and clearly legible to the examiner when they're standing 20 metres from the car.

The font and letter spacing will also have to be uniform and written in a way that can't be misread or misinterpreted.

What an MOT doesn't cover

It's important to remember an MOT is not the same as a car service, and some operational parts of the car will not be checked in your MOT. 

The condition of your cars engine, clutch and gearbox aren't checked in an MOT as they aren't considered safety critical. They are however essential to the running of your car and so you'll need to stay abreast of them with a regular service. While an MOT test is required to keep your car road legal, it does not guarantee the mechanical condition of the vehicle. Carrying out regular servicing will keep your car mechanically sound and could save you big time in the long run.