edited photo of car mechanic checking car engine with the title

Most Common Reasons your Car could fail its MOT & Top Pre-MOT Checks

So you’ve booked your car in for a MOT. In the lead up to D-Day, the heat is on and your brain starts going into overtime wondering what it could possibly fail on. Every journey you take you start to hear new noises. Was that rattle there before? The paranoia sets in and before you know it you’re researching payday loans to cover the imaginary bill. Don’t panic. The chances are your car will pass and if it doesn’t, it’s unlikely it will fail on several counts. In fact, over 50% of MOT’s fail on minor issues with bulbs, windscreens and tyres. In this article, we’ll go through the most common reasons your car could fail its MOT. We’ll also help you be more prepared for your MOT with a handy guide to Pre-MOT checks.

What is a MOT Test for?

A MOT is a means of testing a vehicle and its features for safety. A MOT doesn’t provide a guarantee that a car will be safe to drive for the next 12 months. But what it does do is provide a review of four significant safety systems: brakes, steering, suspension and tyres. If, during the MOT these areas do not meet the standards set then the car will fail the MOT.

If a car fails it’s MOT it is not allowed to be driven on the road until the problem areas are rectified.

New Legislation around MOT testing

The Government announced in January this year that they have plans to increase the MOT age of a car from 3 years to 4 years. This could be music to your ears if you’ve recently purchased a new car. The Government cited the reason behind the change is that the reliability of cars has developed ten-fold since the introduction of the MOT in 1960.

The UK government have taken note of EU minimum requirements. The EU state that MOT test frequency is every two years, with the first MOT taking place when the car reaches 4 years old. Looking at the safety ratings of EU Countries operating the 4-year rule Andrew Jones MP, Parliamentary Under Secretary of State for Transport gave this statement:

“Many other European countries, including France, Ireland, Italy and Spain, as well as Denmark and Norway, which are among a group of countries alongside the UK with very good road safety records, have the first test at four years.”

What is checked during an MOT?

When you take your car in for a MOT there’s a substantial list of parts which are checked to ensure they are in proper working order. They range from the seemingly insignificant to the downright essential but each has a bearing on how safe your vehicle is on the road.

  • Registration Plate
  • Mirrors
  • Lights
  • Wipers and wiper blades
  • Windscreen
  • Vehicle structure
2 great Britain number plates stacked on top of each other one yellow and one white
  • Doors
  • Wheels and tyres
  • Brakes
  • Exhaust emissions
  • Fuel system
  • Steering and
  • Suspension
  • The vehicle’s front seats
  • All seat belts
  • The horn

Check out What is checked in an MOT and Service

mechanic checking and fixing the suspension spring on a car

The Most Common Reasons a Car Fails Its MOT

These are some of the most common reasons a car can fail it’s MOT. So check them ahead of time and make some small repairs to really help improve the chances of your vehicle passing the MOT.

Step One. Check the brake lights.

Park your car with the rear of the vehicle facing a plain white wall,garage door or a window. Turn on the ignition and press the brake pedal. If you look in your rear view mirror you should be able to clearly see the reflection of the brake lights. The brake lights are a crucial safety feature warning vehicles behind you that you are stopping.

Step Two. Inspect the indicators and headlights

Turn your headlights on to dipped and get out to check they are working properly, repeat this step with the full beam, high beam and each indicator. Be sure to check the front and rear indicator lights. If any are not operating it’s probably just the bulb that needs replacing. This is easily done yourself on most makes and models of car. Or, your local Halfords store can often help with small repairs and replacements.

Step Three. Fuel up

The MOT tester will need enough fuel in the tank to carry out emissions checks so never take your car for a MOT on an empty tank. When you fill up the car it’s also worth checking that the fuel cap fits securely. It should be airtight.

Step Four. Beep Beep

The horn is checked during an MOT and is often forgotten by motorists unless you have a habit of road rage? Give it a quick test. You’ll know the sound of a good healthy horn vs one that isn’t fully operational. The middle of the day is the most acceptable time to test your horn. As its loud, I would recommend avoiding before 9am and after 6pm.

women using car horn whilst driving

Step Five. Check your number plate

The numberplate is often forgotten because it’s not actively used by drivers every day. However, it is a crucial part of the car and its safety on the road. Check that the numberplate is securely fastened to the car and is clean and visible. Don’t forget the rear number plate too!

Step Six. Suspension checks

With some of the pot holes around on the roads near me, my suspension takes a daily beating. To check your suspension you must press down heavily on the front wing of the car each side. If it returns to the right position then your vehicle should pass this section of the MOT. If you notice that the car bounces up and down then you should be expecting this to come up on the MOT. The typical problem is with the shock absorbers in this case.

Step Seven. Seat manoeuvrability and seatbelts

The driver seat should move back and forth on the runners smoothly and each seat belt should return to their original position once tugged. It is also worth checking the belt itself for any damage like fraying.

red seatbelt warning on dashboard of car

Step Eight. Tyre tread

Checking your tyres is an obvious part of the MOT and if you can be prepared for any problems with your tyres you can get these seen to ahead of time to avoid any nasty surprises. Tyre tread is important and driving when your tyre tread is too low is actually illegal. You can measure your tyre tread by placing a 20p coin in the grooves on the outer edge of each of your tyres. If the 20p sticks out further than the tread of the wheel then your tread is too low and the tyre needs replacing.

Whilst doing this keep an eye for any bulges or other damage to the sidewalls of the tyre such as nails which may have penetrated the rubber or scratched into the outer edges which in time could turn into a tear.

Step Nine. The Windscreen

A certain size of windscreen chip is acceptable but anything over 40mm in diameter would be a fail. On the areas the windscreen wipers move across the size of chip allowed is reduced to just 10mm so be mindful of this.

big chip on windscreen of dark silver car

Step Ten. Windscreen Wipers

These need to be fully operational with no fraying and should clear the screen fully when switched on. Replacement windscreen wipers are a minimal cost and can be easily fitted within seconds. But, they could be the difference between an MOT pass and fail.

By checking these 10 elements of your car at home as a precaution you are safeguarding yourself against a MOT fail. They are simple checks which will only take a few moments but can give you some peace of mind when it comes to your car’s MOT. These are the most common reasons a car can fail it’s MOT, so knowing ahead of time that these are ok and ticking these boxes are a good indication that your car is likely to pass.

Confident that you know how to check your car before the MOT?  If it unfortunately still fails there are things you can do. Make sure you  read our article on what to do if your car fails it's MOT here 

Request a call back from one of our Vehicle Experts

Faye Lindeck

Faye enjoys Music, Dog Walking and Socialising with friends.

Faye is an experienced blogger with a keen eye for finding excellent information about the subjects she writes about. Giving OSV blog readers the most accurate knowledge.
Faye Lindeck

Leave comments

Your email address will not be published.*



You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Back to top