The MOT test is getting a major overhaul next month, with new defect types and stricter rules for diesel car emissions.

Changes will affect cars, vans, motorcycles and "other light passenger vehicles" according to gov.co.uk

Find out when the changes come into force and how they affect you.

When do the changes come into force?

The new changes will come into effect on Sunday, May 20.

Dangerous, Major and Minor defect categories

The defect categories Dangerous, Major and Minor will be introduced to the test in May.

If your vehicle has a Minor issue this will be recorded on its MOT certificate and also online, just as it is now.

For example, if a steering box is leaking oil this would be classed as a Minor fault, however if the oil is leaking to the point that it is dripping, then this would constitute a Major defect and the car would fail the test.

The category the MOT tester gives each item will depend on the type of problem and how serious it is.

MOT testers will still give advice about items you need to monitor. These are known as ‘advisories’.

The new categories, being introduced to meet a new EU directive, will be applied to all cars.

What do the new categories mean?

Item result What it means about the item How it affects your MOT result
Dangerous A direct and immediate risk to road safety or has a serious impact on the environment.

Do not drive the vehicle until it’s been repaired.
Fail
Major It may affect the vehicle’s safety, put other road users at risk or have an impact on the environment.

Repair it immediately.
Fail
Minor No significant effect on the safety of the vehicle or impact on the environment.

Repair as soon as possible.
Pass
Advisory It could become more serious in the future.

Monitor and repair it if necessary.
Pass
Pass It meets the minimum legal standard.

Make sure it continues to meet the standard.
Pass

Diesel

Any car fitted with a diesel particulate filter (DPF) that emits “visible smoke of any colour” will get a major fault, and automatically fail its MOT, according to specialist motor site autoexpress.co.uk .

Testers will also be urged to check to see if the DPFs have been removed or tampered with, and can refuse to test any car if “the DPF canister has clearly been cut open and re-welded”, unless the owner is able to prove this was done for a legitimate reason, such as filter cleaning.

Other changes

Other changes include checking reverse lights and inspecting brake discs to see if they are “significantly or obviously worn”.

These are in addition to checks for oil contamination of the disc, and how securely they are attached to the wheel hubs.

Cars that are more than 40 years old won’t have to take the annual road safety test.

The reasoning behind it is because the Department for Transport believes these cars are “usually maintained in good condition and used on few occasions”.