What's checked in an MOT?

An MOT test is an annual check that ensures that your vehicle meets road safety and environmental standards. Each MOT test includes a list of standard tests and checks that are performed on every vehicle.

We’ve listed below the main elements that are checked as part of the MOT test.

We’ve also included some simple pre-check tests anyone can perform before an MOT. Nearly half of all faults found during an MOT could have been avoided by carrying out simple maintenance, so spending a little time checking items like lights, wiper blades and tyres before your test could save you money, time, and an avoidable failure.

If you do identify a fault, we’ve got all the spares and replacement parts you need at Halfords. In some cases, we can even replace items such as bulbs or wipers for you while you wait.


Your vehicle’s front, rear, brake, fog, indicator and registration plate lights and rear reflectors must:

  • Be correctly positioned
  • Secure
  • Not be obscured
  • Be in good condition
  • Show the correct colour (a bluish tinge to the front headlights is acceptable as long as the predominant colour is white)
  • Not be adversely affected by the operation of any other light
  • Illuminate with a single operation of the switch

Pairs of lights must emit light of the same colour, size and shape and the headlight aim (both dip beam and main beam) should be below the horizontal, so as not to dazzle other drivers.

Any electrical socket must be in good condition and correctly operate the trailer parking lights, brake lights, indicators and rear fog lights.

Pre-MOT check tips - 30% of all MOT faults relate to lighting and signalling - While you operate your lights from the driver’s seat, have a friend or family member walk around your vehicle to check each of them is working correctly.


The horn must emit a continuous uniform note and must be loud enough to be heard by another road user.

Pre-MOT check tips - Give your horn a quick blast to check it’s working correctly.


The battery must be secure and not show any signs of leaking electrolytes.

Pre-MOT check tips - Check that all connectors are in place securely and in good condition. Keep an eye out for fluid leakages. If you have any concerns about the health of your car’s battery then book in for a free battery check for peace of mind.

Electric wiring 

Wiring should be secure and must not be damaged to the point where it is likely to short-circuit or become detached.


Your steering wheel must be secure and in good condition. Our expert technician will check this by pushing the wheel in various directions and inspecting the steering components for wear or damage.

If your steering has a locking device, it should only lock when the engine isn’t running.

Vehicles with power steering must have at least the minimum level of power steering fluid in the reservoir.


Suspension components and shock absorbers will be checked for excessive corrosion, distortion and fractures.


Your brakes, pedals and levers should be in good condition and any relevant warning lights must work. Our expert technician will also carry out a brake performance test to check brake efficiency.

Pre-MOT check tips - 9.6% of MOT fails are due to brake issues - Keep an eye on your car and make a mental note if it pulls to one side when you apply the brakes. Pulling to one side is a serious problem and must be addressed for your safety. Book in for a free brake check and our trained technicians will check your brakes, understand what’s causing the issues and solve it.
Tyre and road wheels

Your tyres must be of an appropriate speed and load rating for your vehicle and tread depth needs to be at least 1.6mm. Our expert technician will check for cuts in excess of 25mm, lumps, bulges, tears, exposure of the cord and tread separation.

For vehicles with run-flat tyres, the warning light must operate correctly.

Road wheels must be in good general condition, and all-wheel nuts should be in place and tightly secured.

Pre-MOT check tips - 10% of all MOT faults are related to tyres - Before taking your car in for an MOT, use a tyre depth gauge to check the tread depth of each tyre. If you don’t have the tools or the time, drop into your local Halfords auto centre for a free tyre check.

Seat belts

All your seat belts (including the attachment and adjustment fittings) need to be the correct length and in good working order.

Pre-MOT check tips - Give your seat belts a sharp tug to make sure that the restraint system works. Check the locks operate correctly and everything is in good working order.

A general inspection of the body, chassis, engine mountings, seats, bonnet, boot and doors will be checked making sure all components are free from excessive corrosion with no sharp edges that might cause injury.

Registration plates

These must be secure and clearly legible to someone standing 20 metres away from the car and fitted to the front and rear of the vehicle, all characters must be correctly formed and spaced so they are not misread.

Pre-MOT check tips - Clean your number plates and make sure they’re legible and legal. If you need replacement registration plates for your front or back, you can order one online.

Vehicle Identification Number (VIN)

Every vehicle must permanently display a legible VIN, either on a VIN plate secured to the vehicle, stamped or etched on the body or chassis.


A speedometer must be fitted, and our expert technician will check that it can be illuminated. It doesn’t matter if the dial glass is cracked as long as the speed can be read.

Pre-MOT check tips - Check that your speedometer can be read and the dashboard lights illuminate at night.
Exhaust system

Your exhaust system should be secure and free of leaks. If your vehicle was originally fitted with a catalytic converter, it must still be present.

Pre-MOT check tips - Make a note of any noise or rattling from the direction of your exhaust pipe when your car’s running, this could suggest a problem that needs addressing before you take your MOT. Take advantage of our free exhaust check to get some expert analysis and support.


Your vehicle’s carbon monoxide and hydrocarbon emissions must fall within the legal limit. Our expert technicians will use a gas analyser probe while the engine is running to test the smoke emitted from the exhaust. They’ll also visually check for excessive smoke of any colour being emitted from the exhaust, which could result in an MOT failure.

Your vehicle will need sufficient engine oil and fuel levels in order for the technician to carry out their emission checks.

Pre-MOT check tips - Be sure to top up your engine oil and fuel before your test. Your oil level should be between the minimum and maximum marks on the dipstick in the oil reservoir under your bonnet.


Rearview mirrors and wing mirrors must be secure and provide adequate views to the rear and side of the vehicle.

Pre-MOT check tips - 6.6% of MOT fails are due to issues with the driver's view of the road - Check for cracks in the windscreen or mirrors that might obscure your view of the road and replace or repair anything that’s damaged. If you notice any chips in your windscreen please book with us for a windscreen chip repair.

Windscreen and wipers

In the area of the windscreen directly in front of the driver, there must not be any damage or obstruction to the view larger than 10mm. Outside this area (but within the swept area), there must not be any damage or other obstruction larger than 40mm. Wipers and washers must sweep a wide enough area to give the driver an adequate view of the road.

Pre-MOT check tips - Give your wiper blades a once-over to ensure they’re in good working order and aren’t showing any signs of damage. Following this check screen wash levels and top up if needed. Give it a squirt and ensure everything is working as it should be setting off for your test.

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