Major vs Minor MOT Defects Explained: What Each Grade Means for Your Car
Last updated: 11 November 2026
Every MOT result in the UK uses the same four defect grades: dangerous, major, minor and advisory. If you are short on time, here is the difference that matters most.
The direct answer: a major defect means your car has failed its MOT — the fault may affect road safety, put other people at risk, or damage the environment, and it must be repaired and retested before the car can legally be driven (except to a pre-booked repair or retest). A minor defect means your car has passed — the fault has no significant effect on safety or the environment, but it should be repaired as soon as possible, because minor faults left alone often become major ones by the next test.
In this guide we explain all four MOT defect grades in plain English, with real examples of each, what each one means for driving your car, how retests work, and how to use the grades when you read an MOT history record before buying a used car.
The Four MOT Defect Grades at a Glance
Since May 2018, every fault an MOT tester finds is graded using the categories in the DVSA’s MOT inspection manual. The grade — not just the fault — decides whether the car passes or fails.
| Grade | Result | What it means | Can you drive the car? |
|---|---|---|---|
| Dangerous | FAIL | A direct and immediate risk to road safety, or a serious risk to the environment | No — the car must not be driven until it is repaired |
| Major | FAIL | A fault that may affect safety, put other road users at risk, or harm the environment | Only to a pre-booked repair or retest; otherwise no |
| Minor | PASS | A fault with no significant effect on safety or the environment | Yes — but repair it as soon as possible |
| Advisory | PASS | An item that could become a problem in future, or needs monitoring | Yes — keep an eye on it |
If you are reading an MOT history and want to understand the advisories on it, our guide to what an MOT advisory means explains the difference between an advisory and a defect in detail.
What Is a Major MOT Defect?
A major defect is a fault serious enough to fail the MOT. The DVSA definition is that the defect “may affect the vehicle’s safety, put other road users at risk or have an impact on the environment”. The word “may” matters: the tester does not have to prove the fault caused an accident — if it could make the car unsafe, it is major.
Major defects are by far the most common reason cars fail — lights, tyres, brakes, suspension and emissions. Our guide to the most common MOT failure reasons in the UK ranks them and explains the cheap checks that catch most of them before test day.
Examples of major defects
- Brakes: brake pads worn below the limit, a brake disc scored or cracked, brake fluid leaking, or the parking brake not holding the car.
- Tyres: tread depth below the legal minimum of 1.6 mm across the central three-quarters of the tyre, a cut deep enough to expose cord, a bulge in the sidewall, or the wrong size tyre fitted.
- Lights: a headlamp not working, a brake light out, indicators flashing at the wrong rate, or a headlamp aim so far off that it dazzles other drivers.
- Steering and suspension: excessive play in a steering joint, a broken coil spring, a leaking shock absorber, or a worn suspension bush that affects handling.
- Emissions: exhaust emissions above the limit for the car’s age and fuel type, a missing or tampered diesel particulate filter (DPF), or a warning light showing an emissions fault.
- Body and structure: sharp edges from corrosion that could injure a pedestrian, a seatbelt that does not retract or latch, or a windscreen crack in the driver’s line of vision.
What Is a Minor MOT Defect?
A minor defect is a fault that the tester has noticed but which has no significant effect on the vehicle’s safety or the environment. The car passes its MOT, the defect is recorded on the pass certificate, and — this is the part owners most often misunderstand — you are still expected to get it fixed.
Minor defects replaced the old “pass with advisory” grey area for small faults. Before 2018, a tester who found a small problem would usually note it as an advisory. Now, if the fault is a genuine (if small) defect against the manual, it is recorded as minor — a formal grade, not a casual note.
Examples of minor defects
- Registration plate: a number plate lamp that is dim or flickering, or a plate with slightly faded characters that are still readable.
- Wipers and washers: a wiper blade starting to smear, or a washer jet that is partially blocked.
- Small leaks: a slight oil or fluid weep that is not dripping onto the road or a hot component.
- Bodywork: a small area of non-structural corrosion with no sharp edges, or a mirror with a small crack that does not affect the driver’s view.
The important thing about a minor defect is its direction of travel. A wiper that smears slightly this year will smear badly next year, and a small leak or a worn bush will not repair itself. A car that collects several minor defects in one year very often collects major defects the next.
Major vs Minor: The Differences That Matter in Practice
1. Pass or fail
This is the headline difference. Major means fail; minor means pass. Everything else — the repair bill, the retest, whether you can drive the car — follows from this one fact.
2. Whether you can drive the car
With a minor defect, you can drive away and carry on as normal. The car has a valid MOT certificate, and your insurance remains valid on that point.
With a major defect, the position is tighter. If your previous MOT certificate is still in date, you can drive the car to a pre-booked repair appointment or retest — but not for general use. If your old MOT has already expired, you may only drive to a pre-booked MOT test or to a place where repairs will be carried out. Driving a car with a known major defect for anything else risks a fine of up to £1,000, and if the car is in a dangerous condition the fine can rise to £2,500 with penalty points or a driving ban. The GOV.UK guidance on getting an MOT sets out the rules.
3. The repair bill
Minor defects are usually cheap: a wiper blade, a bulb, a washer jet. Major defects range from cheap (a bulb, a tyre) to expensive (a DPF, suspension work, brake overhaul). The grade itself does not set the price — the fault does.
4. The retest
A car that fails on a major defect must be retested after the repair. If it is left at the same test station and retested within 10 working days, the retest is free for most items (the partial retest). A full retest — charged for — applies when the car is taken away, when the retest is more than 10 working days later, or when the failure was on certain items such as emissions. A car with only minor defects needs no retest at all: it already has a pass certificate valid for 12 months.
Where Do Dangerous Defects and Advisories Fit In?
Many owners confuse the four grades, so it is worth placing major and minor in their full context.
Dangerous sits above major. It is the only grade that means the car must not be driven at all — not even to a pre-booked repair. A dangerous defect is a direct and immediate risk: a brake that has failed, a wheel about to come off, a fuel leak near a hot exhaust. Our guide to dangerous MOT defects explained covers what counts and the penalties for driving one.
Advisory sits below minor. An advisory is not a defect at all — it is the tester’s note that something could become a problem, such as a tyre close to the legal limit or slight play in a joint that is not yet excessive.
Put together, the scale runs like this:
Dangerous (fail, do not drive) → Major (fail, repair and retest) → Minor (pass, repair soon) → Advisory (pass, monitor).
How to Read Major and Minor Defects in an MOT History
Anyone can check a car’s MOT history free on GOV.UK — you only need the registration number. Our walkthrough on how to read an MOT history report explains the full record field by field. For the defect grades, read the history in date order and look for these patterns.
Illustrative sample: one car, three years of tests
The table below is an illustrative sample created for this guide. It is not a real vehicle’s record — the registration and mileages are made up to show the pattern.
| Test date | Result | Mileage (illustrative) | Defects recorded |
|---|---|---|---|
| 14 March 2024 | PASS | 42,100 | 1 minor: nearside wiper blade smearing. 1 advisory: front tyres 3 mm. |
| 12 March 2025 | FAIL then PASS | 51,300 | 2 major: offside front tyre below 1.6 mm; nearside headlamp aim too high. Repaired and passed the same day. |
| 10 March 2026 | PASS | 60,800 | 1 minor: slight oil weep from sump. No advisories. |
This is a healthy pattern. The minor defect in 2024 (a wiper) was fixed. The advisories in 2024 (tyres at 3 mm) became a fail in 2025 — exactly the direction of travel to expect — and the owner fixed both faults the same day.
Patterns that should worry you
- The same major defect year after year. A car that fails on the same suspension joint or the same brake fault in consecutive years is not being repaired properly — or is being patched just enough to pass. Our guide to repeated MOT failures explains how to read this pattern.
- A growing stack of minor defects. One minor defect is normal. Four or five in a single year, especially on an older car, suggests maintenance is being deferred across the board.
- Major defects that were never retested at the same station. A fail followed by a pass days later at a different test centre is not necessarily suspicious, but combined with other warning signs it deserves a question to the seller.
- A sudden jump from clean passes to a long fail list. This often means the car changed hands, or that a period of neglect ended with a test the car was not prepared for.
If you believe your car was failed incorrectly, you can appeal to the DVSA using form VT17 within 14 working days of the test, and the DVSA will arrange a re-examination. Do not have the car repaired before the appeal inspection, because the DVSA needs to see it in the condition it was tested in. A tester cannot “downgrade” a major defect to a minor one to help you pass — the grade is set by the manual, and the result is recorded centrally within minutes of the test.
What to Do When Your Car Gets a Major Defect
- Read the failure sheet carefully. The VT30 refusal certificate lists every major and dangerous defect. Ask the tester to show you the fault on the car if anything is unclear.
- Get a written quote first. You are not obliged to have the work done at the test station, but driving the car elsewhere is only lawful if you are going to a pre-booked repair — and only if the defect is not dangerous.
- Keep the receipts. If you sell the car later, a folder of repair invoices turns a failed MOT from a red flag into a story of proper maintenance.
- Book the retest within 10 working days at the same station to qualify for a free partial retest where it applies.
- Fix the minor defects at the same time. The car is already on a ramp. A wiper blade or a bulb costs little while the car is in the workshop, and clearing them now keeps next year’s test clean.
What to Do When Your Car Gets Only Minor Defects
Do not ignore them. A pass certificate does not mean the car needs nothing: ask the tester which minor defects are most urgent, fix them within a few weeks rather than a few months, and work through the advisories at the same time. Minor faults are cheap to fix early and expensive once they grow — and a history of passes with minor defects fixed promptly is exactly what a careful buyer wants to see when you come to sell.
Major vs Minor: Quick Answers
Does a minor defect affect my insurance? No. The car has a valid MOT, and a minor defect is not a reason for an insurer to refuse a claim. A dangerous defect, by contrast, can create problems if you drive the car knowing about it.
Can I sell a car with a major defect? Yes, but you must describe it honestly. Selling a car that has just failed its MOT without telling the buyer can breach consumer law, and a car with an outstanding fail is worth less than the same car with a fresh pass.
Do minor defects appear on the MOT history? Yes. Every defect grade — dangerous, major, minor — and every advisory is recorded against the car’s history on GOV.UK. That is why the history is such a useful tool for buyers: it shows not just whether the car passed, but how well it has been looked after.
The Bottom Line
A major defect fails the MOT and must be repaired and retested; a minor defect passes but should still be fixed soon. The grade is decided by the DVSA’s inspection manual, not by the tester or the garage, and every grade is recorded on the car’s public MOT history. Read the history before you buy, fix minor defects before they become major ones, and never drive a car with a dangerous defect.
To see what the grades look like on a real record, run a free check at our check MOT history tool, and read the record with our guide to how to read an MOT history report.
Sources
- GOV.UK — Getting an MOT (test rules, driving without an MOT, retest rules)
- DVSA — MOT inspection manual for private passenger and light commercial vehicles (defect categories and test standards)
- GOV.UK — Check the MOT history of a vehicle (the free official record)
What is the difference between a major and a minor MOT defect?
A major defect is a fault that makes the car unsafe or illegal to drive, so the car fails its MOT. A minor defect is a small fault that does not make the car dangerous, so the car still passes, but the fault is recorded and should be fixed.
Can I drive my car with a major MOT defect?
No. A major defect means the car has failed its MOT and is not roadworthy, so driving it could lead to a fine of up to £2,500, points on your licence, and your insurance being invalid. The only exception is driving to a pre-booked repair or retest.
What happens if my car fails its MOT with a major defect?
You can have the fault repaired at the same test station or take the car elsewhere for repair. If the repairs are done within 10 working days, you can get a partial retest, which only checks the failed items and usually costs less than a full test.
Do minor MOT defects need to be fixed?
Yes, they should be. Minor defects do not cause a fail, but they are recorded on the car’s MOT history and often develop into major defects if ignored. Fixing them early is usually cheaper than waiting for the fault to get worse.
How do I check major and minor defects on a car’s MOT history?
Enter the registration number on the free GOV.UK MOT history checker. It lists every test with the result, the defects found, and whether each one was classed as dangerous, major or minor, so you can see the full history before you buy.