Dangerous, major and minor MOT defects explained

When an MOT tester finds a problem, they don't just write "fail". Every item is placed in a category that tells you how serious it is. Since 20 May 2018 there have been three defect categories (dangerous, major and minor) plus advisories, which aren't defects at all. Understanding them tells you three things: whether the car passed, whether you can drive it home, and how urgently you need to spend money.

The four categories at a glance

Dangerous defects

A dangerous defect means the tester believes the vehicle poses an immediate risk. Typical examples include:

• brake pipes or hoses that are leaking or so corroded they could burst
• tyres with exposed cords or serious cuts and bulges
• steering components that are loose or close to separating
• suspension springs that have broken in a way that affects the tyre
• seriously damaged or insecure structural parts

With a dangerous defect, the vehicle fails and must not be driven until the fault is repaired, even if your previous certificate still has months left on it. Driving a vehicle in a dangerous condition can lead to a fine of up to £2,500, 3 penalty points and a possible driving ban.

In practice, most garages will repair dangerous items on the spot or arrange recovery. If you're testing somewhere that doesn't do repairs, plan how you'll move the car before you book.

Major defects

Major defects are faults that must be fixed but don't usually pose an immediate danger. Common examples include:

• a headlamp aimed far too high or too low
• brake pads below the minimum thickness
• excessive play in a suspension joint
• a windscreen chip or crack in the driver's main field of view
• emissions above the limit for the vehicle
• an inoperative brake light or indicator

A major defect means a fail. Whether you can drive away depends on your current certificate:

1. If your old MOT is still valid, you can legally drive the car, but you should get the fault fixed promptly.
2. If your old MOT has expired, you can only drive to a pre-booked repair or retest.

This is one reason to test in the month before expiry. Our guide on how early you can MOT a car explains how to do it without losing days.

Minor defects

Minor defects are recorded on a pass. They're genuine faults, but they don't significantly affect safety or the environment. Examples include:

• a number plate lamp not working
• a slightly damaged seatbelt that still works correctly
• a small fluid leak that isn't dripping excessively
• a dashboard warning light that isn't working, where the system itself is fine

The certificate is issued, but you should repair minor defects as soon as you can. A minor defect that's ignored can become a major one by the next test.

Advisories

Advisories aren't defects. They're notes about items that are worn or deteriorating but still within limits, such as tyres close to the minimum tread. They don't affect the result. Our dedicated guide to MOT advisories explains how to prioritise them.

How the categories appear on your results

After the test, you'll get either a pass certificate or a "refusal of an MOT test certificate". Both list everything the tester recorded, grouped by category. The same information is stored in the DVSA database and appears in the vehicle's public MOT history.

You can see every defect ever recorded for a vehicle, colour-coded by severity, with our MOT advisories check.

Results from before May 2018

Older tests use different terms. A fail lists "reasons for rejection", and advisories appear separately. You might also see PRS, short for "pass after rectification at station". It means a defect was found and fixed during the same visit, so the vehicle passed. PRS items are a good sign: the problem was dealt with immediately.

Retests

If your vehicle fails, the retest rules depend on where and when the repairs are done:

The items eligible for a free next-day retest are generally simple ones, such as lights, wipers, mirrors and number plates. Ask the test centre what applies to your fail before you leave.

Disagreeing with a result

If you think a defect was recorded wrongly:

1. Speak to the test centre first. Ask them to show you the problem and explain the category.
2. Don't repair the item yet. If you want to appeal, DVSA needs to see the vehicle in the condition it was tested.
3. Appeal to DVSA quickly using the process on GOV.UK. There's a short deadline.
4. Keep your paperwork, including the refusal certificate and any photos.

If the test was a pass but you believe a defect was missed, you can also report it to DVSA.

Defects found outside the MOT

The categories are used at MOT tests, but the law on vehicle condition applies all year round. Police and DVSA officers carry out roadside checks, and a vehicle found with serious defects can be prohibited from being driven until it's repaired, even if it has a valid MOT certificate.

A valid certificate only shows the vehicle met the standard on the day of the test. If a tyre wears down to the cords or a brake pipe starts leaking a month later, the driver is responsible. That's why it's worth acting on advisories and minor defects rather than waiting for the next test.

What the categories mean when buying a used car

The categories give you a quick read on how a car has been looked after.

• Dangerous defects in the history mean the car was, at that point, genuinely unsafe. Ask what happened and who fixed it.
• Repeated major defects in the same area suggest the problem keeps returning, or was patched rather than fixed.
• Lots of minor defects on passes tell you the owner was happy to leave small faults unfixed.
• Clean passes with occasional advisories are what a well-maintained car usually looks like.

Combine this with the mileage readings and advisories. Our guide to reading MOT history before buying walks through the whole process.

A quick way to read your results

When you get your results, sort them into three lists: what must be fixed before you drive (dangerous), what must be fixed to pass (major) and what you should plan for (minor and advisories). That gives you a clear order of priority and a sensible budget, and it's exactly how a good garage will approach the work.

Summary

Dangerous means stop. Major means fix it before you can pass, and drive only if your old certificate is still valid. Minor means pass, but repair it soon. Advisories mean keep an eye on it. Learn those four words and an MOT result stops being a mystery.