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SEAT Mii Mk1 (AA) (2012-2020) reliability

At a glance

SEAT Mii Mk1 (AA) built around 2018: about average at the MOT

SEAT Mii Mk1 (AA) models built around 2018 fail their MOT a little less often than similar cars the same age.

Looking at a SEAT Mii Mk1 (AA) right now?

Enter its number plate to see its full MOT history, risk rating and running costs.

Key figure

15% of MOT tests on SEAT Mii Mk1 (AA) models built around 2018 ended in a fail (retests included), against 18% for similar cars the same age.

Most common issue

The most common MOT issue on SEAT Mii Mk1 (AA) models built around 2018 involves the tyres.

SEAT Mii Mk1 (AA)
No reliability rating: too close to call between ratings2012-2020HatchbackPETROL / ELECTRICITY

Based on 21,825 tests of Mii models registered 2012-2020.

About 1 in 50 Mii Mk1 (AA) MOTs (2%) failed and still hadn't passed 3 days later. That's for cars built around 2018 (7 years old), all fuels combined.

Based on 1,574 tests (DVSA MOT results, 2025). A fail that passed a retest within 3 days, even the same day, isn't counted. Nor is a fail with no later MOT on record.

About 1 in 30 Mii Mk1 (AA) MOTs (3.2%) found at least one dangerous defect. These are cars built around 2018 (7 years old).

Based on 1,574 tests (DVSA MOT results, 2025). Dangerous is the most serious grade an MOT gives: a direct risk to road safety.

Mk1 (AA) fail rate by age

Below typicalAbove typicalHigh (28% or more)Highest fail rateUK average for cars this age
Age / builtFail rateMOT tests
4 yearsbuilt around 2021
15413.0%
5 yearsbuilt around 2020
55411.2%
6 yearsbuilt around 2019
1,65014.4%
7 yearsbuilt around 2018
1,57415.1%
8 yearsbuilt around 2017
2,11119.4%
9 yearsbuilt around 2016
3,05321.3%
10 yearsbuilt around 2015
3,70819.9%
11 yearsbuilt around 2014
4,02521.6%
12 yearsbuilt around 2013
3,94423.0%
13 yearsbuilt around 2012
1,05223.4%

Fail rate is the share of MOT tests that ended in a fail. Retests count as tests. How we count fail rates Build years are worked out from age, so they are approximate. Tests counted are 2025 MOTs. Highest fail rate at 13 years old.

How the Mii Mk1 (AA) compares

At each age below, see how the Mii Mk1 (AA) holds up against other cars the same age. The averages combine all fuel types.

Based on 70,337 tests across 7 SEAT models, built around 2018 (7 years old).

Below typicalAbove typicalHigh (28% or more)Highest fail rateSEAT average
Age / builtFail rateMOT tests
4 yearsbuilt around 2021
15413.0%
5 yearsbuilt around 2020
55411.2%
6 yearsbuilt around 2019
1,65014.4%
7 yearsbuilt around 2018
1,57415.1%
8 yearsbuilt around 2017
2,11119.4%
9 yearsbuilt around 2016
3,05321.3%
10 yearsbuilt around 2015
3,70819.9%
11 yearsbuilt around 2014
4,02521.6%
12 yearsbuilt around 2013
3,94423.0%
13 yearsbuilt around 2012
1,05223.4%

Fail rate is the share of MOT tests that ended in a fail. Retests count as tests. How we count fail rates Build years are worked out from age, so they are approximate. Tests counted are 2025 MOTs.

What to check before viewing

The model's most common MOT issues, turned into things you can ask about or look for.

Brake discs

High priority

Ask for the date and mileage of the last disc replacement; visually check for a deep wear lip and rust pitting on each disc.

Brake pads

High priority

Ask when the pads were last replaced and check the warning-light history.

Tyres

Worth checking

Check tread depth across the full width on all four; uneven wear suggests alignment or suspension issues.

Suspension bushes and joints

Worth checking

Listen for knocks over speed bumps and ask about recent control-arm or anti-roll-bar work.

Vehicle-specific check

Worth checking

Check the car’s number plate on MOT Wise to see its own MOT history and any recalls for its build years.

Other hatchbacks to compare

Other hatchbacks, with each one's figures taken at the same age as the Mii Mk1 (AA).

  1. 1

    Volkswagen up!

    Same body type, tested at the same age

    Fail rate
    14.2%
    Still registered at 10 years
    96.7%

    No clear edge over the SEAT Mii Mk1 (AA) on these figures.

    Some figures could not be compared for these two cars. So this comparison uses the fail rate, share still registered and recalls only.

    15,657 MOT tests on cars built around 2018

  2. 2

    DS 3

    Same body type, tested at the same age

    Fail rate
    24.5%
    Still registered at 10 years
    90.9%

    No clear edge over the SEAT Mii Mk1 (AA) on these figures.

    3 critical recall campaigns matching this model/build period.

    6,861 MOT tests on cars built around 2018

  3. 3

    Toyota Aygo

    Same body type, tested at the same age

    Fail rate
    13%
    Fail, no pass in 3 days
    1.2%
    Dangerous
    4.6%
    Still registered at 10 years
    96%

    Lower fail rate: 13.0%, against 15.1% for the SEAT Mii Mk1 (AA), both built around 2018.

    25,028 MOT tests on cars built around 2018

  4. 4

    Suzuki Celerio

    Same body type, tested at the same age

    Fail rate
    13.9%
    Fail, no pass in 3 days
    1.5%
    Dangerous
    2.4%
    Still registered at 10 years
    93.5%

    Fewer dangerous faults: 2.4%, against 3.2% for the SEAT Mii Mk1 (AA).

    5,662 MOT tests on cars built around 2018

Fail rate
= the share of MOT tests that ended in a fail. Retests count as tests.
Fail, no pass in 3 days
= the share of MOT tests that failed and still hadn't passed 3 days later. A fail that passed a retest within 3 days, even the same day, isn't counted.
Dangerous
= the share of MOT tests where the tester marked a fault as dangerous. It is against the law to drive the car until it is fixed.
Still registered at 10 years
= the share of cars still registered (taxed or declared off the road) 10 years after they were first registered.

How many are still registered

95%of all SEAT Mii cars first registered in 2014 to 2015 were still registered 10 years later. This is the whole model, not only this generation.

UK average for cars first registered in 2014 to 2015: 92% · About typical

The share still registered can reflect demand, the cost of repairs, exports, write-offs and how owners use the car. It isn't proof of how long the car lasts mechanically.

Source: DfT vehicle licensing statistics (VEH0124).

Recall context

6 recalls in all

5 of the 6 Mii Mk1 (AA) recalls cover cars built in these years.

  • 1 Critical
  • 4 more

Top concerns

  • Driver's airbag may not deploy correctly
  • Damaged battery cells could have been installed in the high voltage battery which could lead to a thermail overload
  • Towing eye may be defetcive

For the exact car, check GOV.UK's recall checker with the number plate.

What has gone wrong on Mii Mk1 (AA) cars built around 2018

The share of petrol cars that have ever failed an MOT on each part of the car. Based on 96 cars.

Structural systems

Suspension
6%
Emissions
3%

Wear items

Tyres
11%
Brakes
7%
Lighting
6%
How Mii Mk1 (AA) cars have aged

How Mii Mk1 (AA) cars have aged

How fail rates have changed as these cars got older. Each line follows cars first registered in about the same year across several years of MOT data. Not a prediction for any one car.

0%10%20%35791113Age at MOTBuilt around 2020, 3 years old at the time of MOT: 12.8% (179 tests, 2023 data)Built around 2020, 4 years old at the time of MOT: 9.5% (169 tests, 2024 data)Built around 2020, 5 years old at the time of MOT: 9.9% (161 tests, 2025 data)2020Built around 2019, 3 years old at the time of MOT: 8.2% (1,191 tests, 2022 data)Built around 2019, 4 years old at the time of MOT: 9.6% (1,142 tests, 2023 data)Built around 2019, 5 years old at the time of MOT: 11.4% (1,146 tests, 2024 data)Built around 2019, 6 years old at the time of MOT: 14.5% (1,115 tests, 2025 data)2019Built around 2018, 3 years old at the time of MOT: 10.1% (1,060 tests, 2021 data)Built around 2018, 4 years old at the time of MOT: 12.5% (1,030 tests, 2022 data)Built around 2018, 5 years old at the time of MOT: 13.9% (958 tests, 2023 data)Built around 2018, 6 years old at the time of MOT: 14.0% (949 tests, 2024 data)Built around 2018, 7 years old at the time of MOT: 15.6% (957 tests, 2025 data)2018Built around 2017, 4 years old at the time of MOT: 13.2% (1,249 tests, 2021 data)Built around 2017, 5 years old at the time of MOT: 13.8% (1,201 tests, 2022 data)Built around 2017, 6 years old at the time of MOT: 13.7% (1,142 tests, 2023 data)Built around 2017, 7 years old at the time of MOT: 16.4% (1,160 tests, 2024 data)Built around 2017, 8 years old at the time of MOT: 18.0% (1,148 tests, 2025 data)2017Built around 2016, 5 years old at the time of MOT: 15.9% (1,887 tests, 2021 data)Built around 2016, 6 years old at the time of MOT: 16.6% (1,847 tests, 2022 data)Built around 2016, 7 years old at the time of MOT: 17.5% (1,825 tests, 2023 data)Built around 2016, 8 years old at the time of MOT: 18.6% (1,817 tests, 2024 data)Built around 2016, 9 years old at the time of MOT: 20.8% (1,837 tests, 2025 data)2016Built around 2015, 6 years old at the time of MOT: 14.4% (2,218 tests, 2021 data)Built around 2015, 7 years old at the time of MOT: 15.0% (2,173 tests, 2022 data)Built around 2015, 8 years old at the time of MOT: 17.5% (2,174 tests, 2023 data)Built around 2015, 9 years old at the time of MOT: 18.1% (2,137 tests, 2024 data)Built around 2015, 10 years old at the time of MOT: 20.3% (2,155 tests, 2025 data)2015Built around 2014, 7 years old at the time of MOT: 14.3% (2,401 tests, 2021 data)Built around 2014, 8 years old at the time of MOT: 15.7% (2,397 tests, 2022 data)Built around 2014, 9 years old at the time of MOT: 17.5% (2,355 tests, 2023 data)Built around 2014, 10 years old at the time of MOT: 19.3% (2,376 tests, 2024 data)Built around 2014, 11 years old at the time of MOT: 20.2% (2,295 tests, 2025 data)2014Built around 2013, 8 years old at the time of MOT: 18.4% (2,880 tests, 2021 data)Built around 2013, 9 years old at the time of MOT: 19.8% (2,845 tests, 2022 data)Built around 2013, 10 years old at the time of MOT: 21.1% (2,826 tests, 2023 data)Built around 2013, 11 years old at the time of MOT: 22.2% (2,824 tests, 2024 data)Built around 2013, 12 years old at the time of MOT: 23.0% (2,775 tests, 2025 data)2013Built around 2012, 9 years old at the time of MOT: 22.2% (1,213 tests, 2021 data)Built around 2012, 10 years old at the time of MOT: 21.1% (1,154 tests, 2022 data)Built around 2012, 11 years old at the time of MOT: 23.4% (1,143 tests, 2023 data)Built around 2012, 12 years old at the time of MOT: 21.4% (1,058 tests, 2024 data)Built around 2012, 13 years old at the time of MOT: 23.4% (1,052 tests, 2025 data)2012
First registered around 2020First registered around 2019First registered around 2018First registered around 2017
How each part holds up as Mk1 (AA) cars age

How each part holds up as Mk1 (AA) cars age

The share of petrol cars built 2017-2020 that have ever failed an MOT on each part of the car. Rates usually rise with age, but can dip slightly as cars leave the road.

Part of the car6 years7 years8 years
Suspension3%6%13%
Brakes6%7%11%
EmissionsNo figure3%3%
Tyres9%11%16%
Lighting3%6%13%
DrivetrainNo figureNo figure1%
Corrosion1%0%2%

Based on petrol cars in the 2017-2020 build-year band, from 96 to 120 cars at each age.

Mk1 (AA) variants compared
All generations of this modelEnough data

Most common issues on SEAT Miis of this age

This list covers every SEAT Mii built around 2018, whichever generation it is. We don't have a defect list for the Mk1 (AA) on its own.

Most common advisories and fails

In order of the share of MOT tests that recorded each one

  1. 1
    Advisory

    Tyre slightly damaged, cracking or perishing

    16.8%
    Advisory: 416Fail: 29 (7% of the times it was found)
  2. 2
    Advisory

    Tyre worn close to the legal limit or worn on the edge

    12.2%
    Advisory: 273Fail: 8 (3% of the times it was found)
  3. 3
    Advisory

    Suspension arm pin or bush worn, but not moving too much

    8.1%
    Advisory: 149Fail: 39 (21% of the times it was found)
  4. 4
    Advisory

    Brake pads wearing thin

    6.0%
    Advisory: 89Fail: 19 (18% of the times it was found)
  5. 5
    Advisory

    Brake disc worn, pitted or scored, but not seriously weakened

    5.5%
    Advisory: 109Fail: 1 (1% of the times it was found)

Based on 1,574 tests

Looking at a SEAT Mii Mk1 (AA) right now?

Enter its number plate to see its full MOT history, risk rating and running costs.

Frequently asked questions

Built around 2018 (7 years old), the SEAT Mii Mk1 (AA) (2012-2020) fails MOTs at about the rate typical for this age. This is based on 1,574 7-year-old MOT tests from DVSA data. Each retest counts as a test.

*The build year is worked out from the date a car was first used on UK roads. For most cars this matches when it was registered, but imports may differ by a few months.

Data sourced from DVSA MOT History API. From 21,825 MOT tests on SEAT Miis first registered between 2012-2020. These figures are a guide, not a guarantee.