MOT dangerous, major and minor defects explained

Every MOT result sorts problems into categories: dangerous, major, minor and advisory. Only dangerous and major defects cause a fail. Minor defects and advisories are recorded on the certificate so you know what to keep an eye on.

The categories also tell you what to do next, and the dangerous one carries a strict warning. Below we go through each, with examples, what a retest involves and when you should stop driving. This comes from Automaster, a garage at Longcombe Cross near Totnes.

What is a dangerous defect on an MOT?

A dangerous defect means there is a direct and immediate risk to road safety or serious harm to the environment. The car fails, and you should not drive it until the problem has been repaired. Driving a vehicle with a dangerous defect can lead to a heavy penalty.

Examples might include a tyre with the cords showing, a brake that does not work, a seriously corroded structural area or steering that is badly loose. The tester will tell you plainly if a defect is in this category, and it is shown in red on the test result.

What is a major defect and does it fail the MOT?

A major defect may affect the safety of the vehicle, put other road users at risk or have an impact on the environment. The car fails and needs repair and a retest. It is less immediate than a dangerous defect, but it should be dealt with without delay.

Typical examples include a bulb that is not working, a tyre close to or below the legal tread limit, a worn suspension joint, or emissions above the limit. If your current MOT is still valid and there is no dangerous defect, you may be able to continue to use the car, but you should repair it promptly.

What does a minor defect or advisory mean?

A minor defect has no significant effect on safety or the environment. The car passes, but the item is noted for repair as soon as is practical. An advisory is a heads-up about something that could become a problem soon, such as a tyre getting close to the limit or a suspension part showing early wear.

Neither fails the car, but they are worth taking seriously. A pass with advisories is a useful list for planning maintenance and avoiding a fail next year.

• Minor: pass, repair when practical
• Advisory: pass, monitor or plan the work
• Major: fail, repair and retest
• Dangerous: fail, do not drive

Can I drive my car after it fails an MOT?

It depends on the category and on whether your previous MOT is still in date. With a dangerous defect, no. The car should stay off the road until repaired. With major defects and a valid MOT still in force, you may be allowed to drive it, but you remain responsible for keeping it roadworthy, and a car with a major defect can still be unsafe.

If the MOT has already expired, you can only drive to a pre-booked repair or retest appointment, and only if the car is not dangerous. If you are not sure, leave the car with us or ask before driving it.

How does an MOT retest work after a fail?

Once the defects are repaired, the car is retested. The rules about whether a partial retest applies, and whether there is any further charge, depend on where the repairs are made and how soon the car comes back, so ask us when you collect your result.

Repair costs depend on the part, how much labour is involved and whether other worn components are found. We inspect before we quote, and we would not promise a repair without seeing the vehicle. At Automaster you can ask for a quote or call the quote line.