Why Do Cars Fail the MOT? The Top Reasons
Updated 14 October 2026 · Hyde Road Wheels & Tyres team
Key facts
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Lamps, reflectors and electrical: 10.44% of Class 3 and 4 tests and 24.89% of defects found at first test in 2025 to 2026. Source: DVSA data on GOV.UK, www.gov.uk/csv-preview/68e682f5750fcf90fa6fff65/dvsa-mot-03-
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Suspension: 8.90% of tests and 20.49% of defects. Source: same dataset.
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Tyres: 6.23% of tests and 12.94% of defects, but 60.60% of dangerous defects. Source: same dataset.
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Brakes: 6.10% of tests and 15.18% of defects. Source: same dataset.
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Result categories: a vehicle fails if the result lists “dangerous” or “major” problems; “minor” and “advisory” items are for monitoring. Source: www.gov.uk/getting-an-mot/after-the-test
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Dangerous fail: you can be fined up to £2,500, banned from driving and given 3 penalty points for driving a vehicle that failed for a dangerous problem. Source: same GOV.UK page.
What are the most common reasons for an MOT fail?
DVSA publishes initial failures by defect category for Class 3 and 4 vehicles, which covers most cars. For the 2025 to 2026 financial year the biggest categories were:
| Category | % of tests with a defect | % of all defects |
|---|---|---|
| Lamps, reflectors and electrical | 10.44% | 24.89% |
| Suspension | 8.90% | 20.49% |
| Tyres | 6.23% | 12.94% |
| Brakes | 6.10% | 15.18% |
| Steering | 1.94% | 3.59% |
The percentages are shares of initial failures by defect category, so one car can appear in more than one row. Other published lists, such as the RAC’s, use different years and groupings, so their percentages differ. The DVSA dataset above is the primary source.
Why do tyres cause so many dangerous defects?
Tyres account for only 6.23% of tests with a defect, but 60.60% of dangerous defects. That means when a tyre problem is found it is often serious: exposed cord, a bulge, or tread worn below the legal line.
The MOT manual sets the rule. Tread must be at least 1.6mm across the central three-quarters, and a lump, bulge or tear from structural failure is rated dangerous.
Most tyre fails are avoidable with a monthly check of tread, sidewalls and pressure.
Can I drive away after an MOT fail?
It depends on the result. GOV.UK says you can take your vehicle away if your current MOT is still valid and no “dangerous” problems were listed. Otherwise you need to get it repaired before you drive.
Even where driving is allowed, the car must stay roadworthy. If your MOT has run out, you can drive to have the defects fixed or to a pre-arranged MOT appointment, but the vehicle must still meet minimum roadworthiness standards.
A dangerous defect means a fine of up to £2,500, a driving ban and 3 penalty points if you drive the vehicle.
How long do I have to fix it and retest?
Two windows matter.
- Next working day: return to the same test centre by the end of the next working day, and there is no fee for a partial retest on a listed set of items, including lamps, wipers, mirrors, seatbelts, tyre pressure monitoring, and wheels and tyres.
- Ten working days: if you leave the vehicle at the test centre for repair and it is retested within 10 working days, there is no fee for the partial retest. If you take it away for repair and return within 10 working days, a partial retest fee may apply.
Outside those cases you need a full retest and the full fee.
What is an advisory, and what do dangerous, major and minor mean?
An advisory is a note that something is worn or may need attention soon but is not yet a fail. GOV.UK groups “minor” and “advisory” as problems to monitor or fix in future.
Dangerous and major both fail the test. Dangerous means a direct and immediate risk to road safety or a serious impact on the environment. Major means a defect that may affect the vehicle’s safety, put other road users at risk or have an impact on the environment. Source: www.gov.uk/government/news/mot-changes-20-may-2018
Treat advisories as a to-do list. A worn tyre or a pad close to its limit can turn into a fail next year.
Pass versus fail: what can I check first?
Many failures are cheap to prevent. Before the test:
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check every bulb, including number plate lights and the brake lights
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check wipers and washer fluid
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check tyre tread and condition, and the tyre pressure warning light
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look for brake warning lights
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listen for knocks from the suspension on bumps
If a warning light is on, get it diagnosed first. A car that passes these checks at home is less likely to fail on the cheap items.
| Likely to pass | Likely to fail | |
|---|---|---|
| Lights | All bulbs work | Blown bulb or cracked lens |
| Tyres | Above 1.6mm, no bulges | Worn, cut or bulging |
| Brakes | No warning light, no noise | Warning light, grinding |
| Result | Certificate | Dangerous or major listed |
Why do cars fail the MOT in Gorton and Manchester?
Stop-start traffic and rough road surfaces wear brakes, suspension and tyres faster than gentle motorway miles. That fits the DVSA picture: lights, suspension, brakes and tyres lead the failure table.
Hyde Road Wheels & Tyres in Gorton, M12 5FH, is open Monday to Friday 9:00 to 17:30 and Saturday 9:00 to 16:30, closed on Sunday. Check your tyres and lights before you book, then see our MOT service in Manchester for the booking route.
What is the next question if brakes are on the list?
Brakes are the third biggest share of defects found: see signs your brake pads need replacing. For the test’s full scope, read what does an MOT check.
Frequently asked questions
What is the number one reason for MOT failure?
In DVSA's 2025 to 2026 figures, lamps, reflectors and electrical equipment were the biggest single category by share of defects at 24.89%. A blown bulb is a common cause. Check all lights before the test.
What is the difference between major and dangerous?
Both fail the MOT. GOV.UK defines a dangerous defect as a direct and immediate risk to road safety or a serious impact on the environment, and a major defect as one that may affect the vehicle's safety, put other road users at risk or have an impact on the environment. Do not drive a vehicle with a dangerous defect.
Can I get a free retest?
Sometimes. A partial retest within 10 working days after leaving the car at the test centre for repair is free. A partial retest on a listed set of items by the end of the next working day is also free if you return to the same centre.
Does a failed MOT cancel my old one?
If the old MOT is still valid you can drive the vehicle away, provided no dangerous problems were listed. The vehicle must still be roadworthy. Do not rely on an unexpired MOT as permission to drive an unsafe car.
Can I appeal an MOT fail?
Yes. GOV.UK says you can appeal if you think the failure is wrong, and DVSA will contact you within 5 days. If your appeal succeeds, you are refunded the test fee. See https://www.gov.uk/getting-an-mot/problems-with-your-test-result
Need tyres, an MOT or a repair in Gorton?
Ring the garage on 0161 274 3125 or come to 270 Hyde Road. We will tell you what the car needs before any work starts.
Hyde Road Wheels & Tyres, 270 Hyde Road, Gorton, Manchester M12 5FH. Open Mon to Fri 9:00 to 17:30, Sat 9:00 to 16:30.