Our cars have to have annual MOT tests - that's just the way it works. But next time you have it done, you might be seeing a different report.

Starting May 20, new categories of faults will begin to be used by test centres.

Emission tests are also being stiffened up, reports the Mirror.

But you're probably wondering how exactly will it change and how will it affect me? Here's all you need to know.

What are the new fault categories?

One of the biggest edits to the MOT test is the way faults are classified.

The categorisations are Dangerous, Major, and Minor.

New rules coming in May have changed how vehicles are classed after an MOT test

What's the difference between them?

Minor issues are recorded, and the owner advised to get them fixed – but the car will still pass its test. These faults will also be added to the car’s MOT certificate and online record.

Anything resulting in a Dangerous or Major classification will mean an immediate fail.

A Minor issue would be a problem such as oil leaking from a steering box. However, this would escalate to a Major if the leak was so bad as to be dripping.

What's the focus on diesel cars for?

A crackdown on diesel car emissions is evident in the new test. If your diesel car puts out any smoke whatsoever, it won’t pass its MOT examination.

Testers are also being told to do thorough checks of a car’s DPF (Diesel Particulate Filter) to ensure that they haven’t been tampered with – or removed entirely. The guidelines read that: "Any vehicles fitted with a DPF should be checked so that ‘no visible smoke is emitted from the exhaust during the metered check’."

Some diesel drivers remove the filter to boost performance and increase miles-per-gallon, but since it regulates the exhaust gases produced by the engine, this isn’t the most ecological option.

It means that if a car was fitted with a DPF as standard, its removal would mean an instant MOT fail.

Since some drivers remove the internals of the DPF but keep the housing in place, testers are also being asked to check for tampering. That means that if there is any sign that the DPF has been disassembled and then welded back together, the car will fail the test.

Are there any other changes?

Testers are now asked to check whether or not brake discs are worn or corroded, while they must also ensure that they are properly attached to the wheel hubs too.

Another example of a Minor fault is if a brake hose is slightly damaged. However, if it is excessively damaged or twisted, it’ll mean a Major fault – and will cause the car to fail.

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What is being said about the changes?

There have been calls for the Government to simplify the way the MOT test is conducted, with RAC spokesman Simon Williams saying that: “The new system creates the potential for confusion as testers will have to make a judgement as to whether faults are ‘Dangerous’, ‘Major’ or ‘Minor’.


“Motorists may also struggle to understand the difference between 'Dangerous' and 'Major' failures. The current system ensures that any vehicle with a fault that doesn’t meet the MOT requirements is repaired appropriately before being allowed back on the road.”