Since May 2018, the UK MOT test has used a three-tier system for classifying faults. Understanding what each category means helps you know how urgently to act on any issues found during your test.
The three categories
Minor: A fault that has been identified but does not significantly affect the safety of the vehicle or the environment. A minor fault does not cause an MOT failure. The car passes, but the item is noted on your certificate and should be monitored and repaired before it develops further.
Major: A fault that may affect the safety of the vehicle, put other road users at risk, or have an impact on the environment. A major fault causes the vehicle to fail its MOT. The vehicle must not be driven (except to a pre-booked garage for repairs) until the fault is fixed and a retest is passed.
Dangerous: A fault that poses a direct and immediate risk to road safety or the environment. A dangerous fault also causes an MOT failure. The DVSA guidance says that a vehicle with a dangerous fault should not be driven at all, even to a garage for repairs.
Why does the distinction matter
Before 2018, a failure was simply a failure, with no indication of severity. The new system gives drivers clearer information about risk. A dangerous fault (for example, brake failure or a structural crack in a steering component) is significantly more urgent than a major fault (for example, a headlight bulb out).
Can minor faults become major
Yes. An item recorded as a minor advisory in one year can deteriorate and become a major failure at the next test. This is particularly common with tyre tread approaching the legal minimum, minor corrosion on brake components, and small oil leaks. Addressing minor items promptly avoids this.
At Steins Garage we explain every category clearly when we hand back your result. Book your MOT here or call 0131 554 3423.