MOT Defect Categories – What do they mean?

When performing an MOT check on a vehicle you will have undoubtedly come across some categorised notices when scouring through the vehicle’s history (and if you haven’t seen any, congrats on having a well maintained vehicle!)

Here I’ll explain what each of these categories means, and what you need to know about whether your vehicle is safe to drive after an MOT test.

In 2018 the DVSA issued new guidelines on how MOT defects should be categorised. The three new categorisation options are Dangerous, Major and Minor.

MOT testers are given guidance on pre-defined defects marked as Dangerous, Major or Minor. Therefore there is no longer any ambiguity as to the level of severity a defect can be.

What are Major MOT defects?

Major MOT defects lead to an instant fail of the vehicle’s MOT test. They can often be serious issues, but are not immediately classified as dangerous.

Your vehicle will not pass its MOT until you (or a garage) have rectified any Major defects and a re-test taken.

Such Major defects may include “Shock Absorber Has A Serious Fluid Leak” or “Exhaust system has a major leak or is insecure“.

What are Minor MOT defects?

Minor MOT defects are caused by faults on vehicle components deemed less critical. You’ll often find Minor defects on components that have suffered some slight damage but are in full working order.

Your vehicle will not fail an MOT on Minor defects alone.

Statistics tend to show that Minor notices don’t happen very often. It’s very likely that if a component is starting to show wear or become damaged it will immediately be identified as a Major defect, or just an advisory item.

Minor defects can include “Rear Registration Plate Lamp Inoperative” and “An obstruction within the driver’s field of view“.

What are Dangerous MOT defects?

Dangerous MOT defects are the most severe of the failure notices. As with Major defects, they automatically lead to a failure of your MOT test, but have the added kicker of making your vehicle dangerous to drive.

Certainly not a nice notice to get!

This of course now invalidates any remaining days left on the current MOT, and from that point forward it is illegal to drive your vehicle on a public road in this “dangerous” state.

It is essential Dangerous defects are fixed at the nearest opportunity. Such Dangerous defect notices may include “Road Wheel Fractured” or “Brake lining or pad worn below 1.5mm“.

What are Advisories?

Although we now have the three clear categories above, MOT testers can still declare faults as Advisories.

These are the most minor of notices, and should merely serve as warnings that your MOT tester believes a fault may soon become apparent on a particular vehicle component.

Advisories are not mandatory. Your MOT tester doesn’t have to note down or inform you of advisories on your MOT, but any good MOT tester will.

Your vehicle will not fail an MOT with Advisory notices. However failure to rectify any identified advisories may lead to them becoming failure points at the next, or any future, MOTs.

Examples of Advisories can include “Tyre Worn Close To Legal Limit” or “Anti-Roll Bar Linkage Ball Joint Has Slight Play“.

What does PRS mean on your MOT?

In some instances on your MOT history you may find a notice has been added called a PRS, or “Pass with Rectification at Station”.

MOT testers are given the option of adding a PRS notice when they encounter a defect which would fail your MOT, but they have the facilities there and then to rectify it during the course of testing.

For example, you may notice a fail record on your historical MOT check with a PRS notice of “Stop Lamp Not Working“. This means the MOT tester has noted down this test as a Fail, but upon making this simple fix on your behalf, it then immediately switches to a Pass.

This means in the span of one MOT test session your vehicle Failed, then Passed, it’s MOT.

It is rather annoying seeing these notices on your MOT history, but the MOT tester has to record such things in this way to keep accurate statistics and data for the DVSA.

Otherwise the tester could get in trouble if, for example, the DVSA notices that no vehicles ever fail on Stop Lamps at their station…

What about notices before 2018?

Prior to 2018, a somewhat simpler system was in place where an MOT tester would simply note down any defects along with the words “Fail” or “Advisory” – pretty self-explanatory.

If an MOT tester had any other notices that needed mentioning at the time, they could also be added to the check as “User Entered” notes. This may include less important maintenance issues due soon, or things the MOT tester recommends that you keep an eye out for in the next 12 months.

At MOT.Tools we clearly show all notices recorded against your vehicle in our comprehensive MOT history checks.

Hopefully you now understand a little better what each categorisation on these notices actually means.


Do Minor Defects fail an MOT?

A vehicle will not fail an MOT on Minor defects alone. Minor defects are not MOT failures.

Vehicles may have many minor defects noted but will not fail an MOT unless Major or Dangerous defects are noted too.

Do you have to repair Minor Defects?

There is no legal requirement to repair Minor defects on your MOT.

However, prolonging the issues noted in a Minor Defect will generally lead to further degradation of the component in question, so it is advised that issues noted in any minor defects are rectified as soon as possible.

The Minor Defect will continue to be noted by your MOT tester at any further MOTs until it is dealt with appropriately.

Do Major Defects fail an MOT?

Yes, any defects noted on an MOT as Major will cause an MOT failure.

All defects marked as Major must be rectified before your vehicle will next pass an MOT.

Do Dangerous Defects fail an MOT?

Yes, Dangerous Defects are the most severe failure points on an MOT and will lead to an instant failure.

Dangerous defects on your vehicle deem it non-roadworthy and it is unsafe and illegal to use your vehicle on a public highway until any Dangerous Defects are rectified and an MOT passed.