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MOT fail rates

SEAT Mii MOT fail rate by age

How often the SEAT Mii fails its MOT at each age, compared with all cars of the same age, and what it fails on. From 72,945 DVSA MOT tests taken 2022 to 2025.

MOT data updated

At 9 years, the most tested age

MOT fail rate at age 9 (n=11,631)23.4%
All cars at 9 years (n=9,949,012)27.1%
Median mileage at test49,585
All cars, median mileage68,033

131 of 315 model groups with enough tests fail less often at 9 years.

What stands out

  • At 3 years the SEAT Mii fails 11.1% of MOTs (2,764 tests), 1.0 points below the 12.1% for all cars that age. At 13 years it fails 29.7% (1,736 tests), 8.6 points below the 38.3% average.
  • The gap is widest at 13 years: 8.6 points below all cars.
  • Its most common structural or mechanical fail item at 9 years: Service brake performance: excessively binding, at 2.4 per 100 MOTs.

MOT fail rate by age

3 years 13 years 42.1%

Solid line: this model. Dashed line: all cars at the same age.

SEAT Mii: share of MOT tests that failed, by age, against all cars. Ages with fewer than 1,000 tests are not shown.
AgeMOT fail rateTests (n)All carsDifferenceMedian mileage
3 years11.1%2,76412.1%−1.0 pts15,091 miles
4 years12.3%3,96213.4%−1.1 pts19,950 miles
5 years14.4%4,36815.3%−0.9 pts24,612 miles
6 years17.4%6,29817.8%−0.5 pts30,987 miles
7 years19.3%7,73920.6%−1.3 pts37,156 miles
8 years19.9%9,57723.8%−3.9 pts43,358 miles
9 years23.4%11,63127.1%−3.7 pts49,585 miles
10 years25.3%11,17730.3%−5.0 pts55,290 miles
11 years26.7%8,41233.3%−6.6 pts60,976 miles
12 years29.3%5,28136.0%−6.7 pts66,667 miles
13 years29.7%1,73638.3%−8.6 pts71,279 miles

Most common fail items at 9 years

Split into structural or mechanical items and wear items. Wear items (tyres, brake pads, wipers, bulbs) say more about upkeep than about the design.

Structural and mechanical

Fail itemPer 100 MOTs
Service brake performance: excessively binding Major2.4
Fuel cap/sealing device: ineffective Major2
Airbag (SRS) warning light on Major1.8
Suspension arm bush worn Major1.4
Catalyst emissions: Lambda reading after 2nd fast idle outside specified limits Major1.4

Out of 11,631 MOTs. A test with two faults counts twice.

Wear and upkeep

Fail itemPer 100 MOTs
Wipers not clearing screen Major2.7
Side/position light not working Major2.7
Tyre tread below 1.6 mm Dangerous2.3
Headlamp aim: too low Major2.1
Registration plate lamp(s): inoperative in the case of a single lamp or all lamps Major1.4

Out of 11,631 MOTs. A test with two faults counts twice.

Other models at 9 years

ModelMOT fail rateTests (n)All cars
SEAT Ibiza34.5%73,55727.1%
SEAT Leon21.4%64,01327.1%
SEAT Alhambra25.2%9,85027.1%

MOT fail rate by first-use year

Each year has its own page: the fail rate for cars first used that year at each MOT from 2022 to 2025 with at least 1,000 tests, the most common faults at that age, and the car tax and ULEZ rules for that year.

First-use year data updated .

Latest MOT age with at least 1,000 tests for each first-use year.
First usedAge at testMOT fail rateTests (n)All cars
201213 years in 202529.7%1,73638.3%
201312 years in 202529.5%3,50136.0%
201411 years in 202524.7%3,08833.3%
201510 years in 202526.1%2,68930.3%
20169 years in 202525.8%2,24627.1%
20178 years in 202519.8%1,47323.8%
20187 years in 202517.3%1,28020.6%
20196 years in 202515.9%1,30617.8%
20214 years in 202512.7%1,08713.4%

More on the SEAT Mii

Read this with care. A fail rate is not a measure of build quality. How far cars are driven, how they are used and how well owners maintain them all change it, and wear items such as tyres and brake pads are common fails. Compare a model only with cars of the same age. Methodology and limits.

Looking at one SEAT Mii?

These are figures for the model, not for one car. The VetTheCar Buying Report looks at a single car: its MOT tests, defects, advisories and mileage readings.

See an example report Browse the car tools

Source

Contains public sector information licensed under the Open Government Licence v3.0. Source: DVSA anonymised MOT test data, class 4 normal MOT tests, 2022 to 2025. MOT data updated 22 September 2026.

Not affiliated with or endorsed by DVSA. How we calculate these figures · Data sources