2025 MOT results
SEAT Mii common problems
The most common reason a SEAT Mii fails its MOT is a sidelight out, on 8.6% of its 4,489 failed tests in 2025. Against other cars of the same age, 6 faults stand out, the widest gaps being: the airbag light on at 5.7% of failures against 1.2% expected; a weak or uneven footbrake at 8.1% of failures against 2.2% expected; emissions above the limit at 5.8% of failures against 1.6% expected.
- Tests in 2025 18,638 Cars aged three and over
- Failed first time 24.1% 4,489 tests
- Found a dangerous defect 4.8% Unsafe to drive away
- Ended with an advisory 44.4% A problem to watch, not a failure
What fails a SEAT Mii MOT
Each bar is the share of failed SEAT Mii tests with that defect. Where we can compare it with cars of the same registration years, the marker shows what an average car of those ages records (11 of the 12 items below).
Most common reasons for failure
A test can fail for more than one defect, so shares add up to more than 100%.
| Defect | Share of failed tests |
|---|---|
| Position lamp: not working Lamps, reflectors and electrical equipment | 8.6% |
| Service brake performance: excessively binding Brakes | 8.1% |
| Registration plate lamp(s): inoperative in the case of a single lamp or all lamps Lamps, reflectors and electrical equipment | 7.8% |
| Headlamp aim: too low Lamps, reflectors and electrical equipment | 7.1% |
| Suspension arms: pin or bush excessively worn Suspension | 6.8% |
| Tyres: tread depth below requirements of 1.6mm Tyres | 6.7% |
| Wipers: does not clear the windscreen effectively Visibility | 6.2% |
| Fuel cap or sealing device: ineffective Body, chassis, structure | 5.8% |
| Catalyst emissions: lambda reading after 2nd fast idle outside specified limits Noise, emissions and leaks | 5.8% |
| SRS malfunction indicator lamp: warning lamp indicates a fault Seat belts and supplementary restraint systems | 5.7% |
| Coil spring: fractured or broken Suspension | 5.3% |
| Headlamp: not working on dipped beam Lamps, reflectors and electrical equipment | 4.4% |
Source:DVSA,UK Motoring analysis 2025 Updated
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Sidelight out
8.6% of failures 6.1% expected somewhat more often
A sidelight, also called a position lamp, not working. It marks the width of the car at night.
Walk round the car with the lights on and the hazards going; these are the cheapest failures to avoid.
-
Weak or uneven footbrake
8.1% of failures 2.2% expected 3.7 times as often
The footbrake is either weak overall or pulls unevenly across an axle, which the rolling road measures.
A pull to one side under firm braking, or a long pedal, is the sign to get it looked at before a test.
-
Number plate lamp out
7.8% of failures 3.3% expected 2.4 times as often
The lamp over the rear number plate not working, so the plate cannot be read at night.
Walk round the car with the lights on and the hazards going; these are the cheapest failures to avoid.
-
Headlamp aim set too low
7.1% of failures 4.0% expected 1.8 times as often
The dipped beam points lower than it should, so it lights too little of the road.
Nothing to do at the roadside, but a garage resets the aim in minutes; a sagging suspension corner or a heavy boot load can throw it out.
-
Worn suspension bushes
6.8% of failures 4.5% expected 1.5 times as often
Worn rubber bushes in a suspension arm, letting the arm move under load.
Perished or cracked rubber at the inner ends of the lower arms, visible with the wheel turned.
-
Tyre worn below the legal limit
6.7% of failures 8.7% expected somewhat less often
A tyre worn past the 1.6mm legal minimum across the middle three quarters of the tread.
A 20p coin in the main grooves: if the outer band of the coin is visible, the tyre is close to the limit.
Which parts of the car fail
Lamps, reflectors and electrical equipment is the area that most often fails a SEAT Mii, on 37.0% of failed tests. The widest gap against cars of the same registration years is seat belts and supplementary restraint systems, on 6.8% against 2.3% expected.
Failure categories
DVSA's own sections of the test. The marker is what cars of the same registration years record.
| Defect category | Share of failed tests |
|---|---|
| Lamps, reflectors and electrical equipment | 37.0% |
| Brakes | 24.3% |
| Suspension | 19.6% |
| Tyres | 18.1% |
| Visibility | 13.5% |
| Noise, emissions and leaks | 11.1% |
| Body, chassis, structure | 10.9% |
| Seat belts and supplementary restraint systems | 6.8% |
Source:DVSA,UK Motoring analysis 2025 Updated
What testers warn about
44.4% of SEAT Mii tests ended with at least one advisory: a fault the tester found that did not fail the test. On SEAT Miis, these are the items to ask about on a car you are viewing, because they are what the last tester expected to go next.
Most common advisories
Share of all tests, passes included.
| Advisory | Share of tests |
|---|---|
| Tyres: slightly damaged or cracking or perishing Tyres | 14.0% |
| Tread depth: worn close to legal limit or worn on edge Tyres | 13.4% |
| Brake discs: worn, pitted or scored, but not seriously weakened Brakes | 6.7% |
| Suspension arms: pin or bush worn but not resulting in excessive movement Suspension | 6.2% |
| Brake pads: wearing thin Brakes | 3.7% |
| Service brake performance: binding but not excessively Brakes | 3.4% |
| Brake discs: worn, but not excessively Brakes | 2.9% |
| Play in steering rack inner joint(s) Non-component advisories | 2.2% |
| Rigid brake pipes: corroded, covered in grease or other material Brakes | 1.9% |
| Registration plates: deteriorated but not likely to be misread Identification of the vehicle | 1.8% |
| Exhaust system: minor leak of exhaust gases Body, chassis, structure | 1.7% |
| Nail in tyre Non-component advisories | 1.6% |
Source:DVSA,UK Motoring analysis 2025 Updated
SEAT Mii problems: common questions
What is the most common problem with a SEAT Mii?
Of the faults that fail an MOT, “Position lamp: not working” is the most common: it appears on 8.6% of failed SEAT Mii tests. Across categories, lamps, reflectors and electrical equipment is the area that most often fails one, on 37.0% of failed tests.
How often does a SEAT Mii fail its MOT?
24.1% of SEAT Mii tests in 2025 were not passed first time, from 18,638 tests of cars aged three and over. Allowing for the age and mileage of the cars tested, that gives it a UK Motoring Reliability Score of 55 out of 100, where 50 is as expected.
Does anything fail more often on a SEAT Mii than on other cars?
Yes. “SRS malfunction indicator lamp: warning lamp indicates a fault” appears on 5.7% of its failures against 1.2% for cars of the same age, and “Service brake performance: excessively binding” appears on 8.1% of its failures against 2.2% for cars of the same age. Where an item is missing from the national figures for a year, we use the smallest share those figures show, so the comparison never overstates the difference.
Are these the same as breakdowns or known faults?
No. These are the items a tester recorded at the MOT, which covers condition and safety: lamps, brakes, tyres, suspension, corrosion and emissions. A gearbox that is unpleasant, an infotainment screen that has died, or a car that will not start on a cold morning are not part of the test, so they are not in these figures.
Where do the figures come from?
Every normal MOT test of a SEAT Mii aged three and over in Great Britain in 2025, from DVSA's anonymised MOT results. Retests are excluded, and the same fault on more than one wheel counts once.
Data stories to read next
Data sources and methodology
| Figures | Source | Period | Records | Updated |
|---|---|---|---|---|
| MOT defects and advisories | Anonymised MOT tests and results Driver and Vehicle Standards Agency Derived statistics UK Motoring | 2025 | 18,638 MOT tests | 19 September 2026 |
- Shares for defects are of failed tests; shares for advisories are of all tests. A test can carry several defects, so shares add to more than 100%.
- The expected share is what an average car of the same registration years records, weighted by where this model’s failures fall. Where an item is outside the national figures for a year, the smallest share those figures show is used in its place, which is an upper bound, so the comparison never overstates a model’s problems. No expectation is published where less than 80% of the model’s failures can be compared.
- Great Britain only: DVSA does not run MOT testing in Northern Ireland. Cars under three years old are not tested.
- The descriptions of what each part does are general and the same on every model. Every figure comes from the MOT data.
Contains public sector information licensed under the Open Government Licence v3.0.