What you need to know about MOT defect categories

There are 2 main legal safety requirements for vehicles. These are that they must be roadworthy and with a valid MOT. On 20 May 2018, changes resulted in defects being split into different categories. They affect whether the vehicle will pass or fail the MOT and have their own meanings.

Major & Dangerous

Defects are pre-defined into different categories. A dangerous defect will result in a fail for your vehicle. Major ones also usually cause a failure. You should never drive a vehicle that is dangerous; it is not just your safety you are risking but others on the road as well as pedestrians.


The minor category includes vehicle defects which are not serious enough for it to fail the MOT. There are also advisories which are when a vehicle component is not defective but there is an indication that it will become defective.

How This Works

  • Dangerous defects are a direct and immediate risk to road safety and can have a serious environmental impact. This will make your vehicle fail and means that you should not drive it until you have someone repair the issue.
  • Major defects might affect safety or impact the environment. This will result in a failed MOT and you should have someone repair the defect immediately.
  • Minor defects pose no significant issue for safety or impact on the environment. You should get repairs as soon as possible but your vehicle will pass.
  • Advisories are aspects which might become problems in the future. Your vehicle will pass but you also need to keep an eye on these.
  • Vehicles that pass meet the minimum legal standard and you should make sure that it continues to do so.

Remember To Arrange Your MOT

If you ever have any questions about motorhome MOTs or your vehicle, reach out to C&N Car Services. We would be more than happy to help you. Our services ensure you stay safe when on the road so remember to book the ones that you need.

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