SEAT
2,153 MOT tests analysed. sits above the UK fleet average — here's where Mii EVs pass, fail, and end up on the retest sheet.
That's 11.0 points above the UK fleet average across our 1,984 tracked models — a confident result.
Pass
88.5%
Pass-after-fix
2.0%
Fail
9.3%
Avg miles
19,081
Pass + Pass-after-fix + Fail = 100%
Electric and hydrogen vehicles are exempt from all UK clean air zone charges.
Performance by cohort
2 year bands · 2,153 tests
Pass rate is broadly flat across the cohorts — new and old Mii EV examples track each other at the test bay.
Pass
89.2%
Fail
8.0%
PRS
2.4%
Avg mileage at test
19,385 mi
Pass
88.4%
Fail
9.7%
PRS
2.0%
Avg mileage at test
19,006 mi
Cohort = vehicle's first-registration year band. Same model, different generations of build.
The picture
Across 2,153 MOT tests, the Mii Ev returns 88.5% first-time pass — comfortably ahead of the UK fleet average. The single most-logged Major fail is a seriously damaged tyre. A defective wiper blade and worn suspension bushes round out the top three. Average tested mileage sits at 19,081, which is the lens to read those failure rankings through. If you own one and the next test is close, the ranked list below is a sensible pre-test checklist.
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A tyre seriously damaged
78 occurrences · 3.6% of tests
Wiper blade defective
21 occurrences · 1.0% of tests
A suspension pin, bush or joint excessively worn
18 occurrences · 0.8% of tests
A shock absorber damaged to the extent that it does not function or showing signs of severe leakage
16 occurrences · 0.7% of tests
Tyre tread depth not in accordance with the requirements
13 occurrences · 0.6% of tests
A tyre seriously damaged
12 occurrences · 0.6% of tests
A suspension pin, bush or joint excessively worn
12 occurrences · 0.6% of tests
A tyre has a lump, bulge or tear caused by separation or partial failure of its structure. This includes any lifting of the tread rubber
11 occurrences · 0.5% of tests
Windscreen washers not working or not providing sufficient fluid to clear the windscreen
10 occurrences · 0.5% of tests
Windscreen or window damaged or seriously discoloured but not adversely affecting driver's view
9 occurrences · 0.4% of tests
Counts cover Major and Dangerous defects logged at test. Advisory items excluded so this shows why a car was rejected, not just what the tester flagged in passing.
Worst-case fix budget · top 3 failures
£160–£380
If every one of this Mii EV's most-logged Major fails hit at the same MOT, that's the real-world UK garage range. Reality is usually one or two items, not all of them. Open the estimator →
Try the calculator
Build your own retest budget.
Year-band analysis
First-time MOT pass rate split by registration band. Pass rates barely move across bands here, so the year you buy SEAT Mii EV makes little measurable difference to MOT outcomes.
Best band to buy
89.2%
2018–2020 registration
the 2018–2020 band climbs to 89.2% — a 0.8-point improvement. Failures here are mostly wear items: has a bulge, caused by separation or…, fractured or broken — the structural issues that drag down older examples don't appear in the top-10 for this band.
Band to be cautious about
88.4%
2021+ registration
On the 2021-on band, the data shows a 88.4% pass rate against a fleet average of 89.2% on the newer band. The main culprits logged at test: has a bulge, caused by separation or…, ball joint excessively worn, and blade defective. Average mileage on test for this band is 19,006 miles — high-mileage wear items are a recurring theme.
Best band to buy: 2018-2020 (89.2% first-time pass). Worst band to avoid: 2021+ (88.4% pass). That's a 0.8-point spread across 1,728 older tests and 425 newer ones — year of build makes a material difference on this model.
Picked against this car's top failure patterns. Affiliate links to Amazon UK — we earn a small cut at no cost to you. Disclosed up-front, doesn't shape the data.
Item 01 · Amazon UK
Bosch Aerotwin wiper blades
Cheap wipers fail the test on smear streaks. Bosch Aerotwins last a winter and clear a screen properly.
Search Amazon UK
Item 02 · Amazon UK
Digital tyre-tread depth gauge
Five quid for a gauge beats £150 for a retest. UK MOT minimum is 1.6mm — most testers fail anything below 2mm to be safe.
Search Amazon UK
My Motor World · affiliate
Affiliate links — small commission, no extra cost to you.
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Click Mechanic · affiliate
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Mobile mechanic · UK-wide
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Owner reports · Honest John
Verbatim faults logged by owners on honestjohn.co.uk over recent years. We didn't summarise — these are the words people typed in.
What's good
As well as being affordable and cheap to run, the Mii is also enjoyable to drive and comfortable too. It feels solid and surprisingly refined for such a small car - in fact from behind the wheel it's easy to think you're in a larger hatchback.
Complaint that new SEAT Mii will not easily go into 1st gear. Dealer fobs off the complaint. [Otr 1.5" Cam / 28 Spline / 5.5" Automatic Slack Adjuster | Auto Slack 1.5" -28/5.5" Arm Haldex Style | Otr-10211 The Otr 1-1/2" Cam / 28 Spline / 5. 5" Automatic Slack Adjuster Ensures Expertise Built In™, Being Engineered With High-Performing, Hig...FleetPride](https://www.bing.com/api/v1/mediation/tracking?adUnit=11725462&auId=1c7e6556-52c6-4272-a7be-fe50d2f4c7ac&bdc=pb&bidId=9&bidderId=4&cmExpId=RSV&impId=445797643&impTy=1&ldc=rhf2nc
Report of 2013 SEAT Mii reaching 65,000 miles without having the timing belt replaced or any sign of trouble (though probably wise to change belt now).
Report of owner of 2016 SEAT Mii manual being recommended by the dealer to have a transmission oil change at its 3rd annual service.
Report of failure of the cabin ventilation/heater/aircon fan motor of a SEAT Mii.
Source: honestjohn.co.uk · 4 reports indexed
Use the failure ranking as a pre-test checklist or a haggling lever. Treat the headline pass rate as a fleet-wide trend, not a guarantee on any individual car.
If you own a Mii EV and your last MOT looked nothing like the ranked failures above, that's normal — individual cars vary widely. The ranking shows the patterns testers flag most often across the country.
