2017 SEAT Mii — MOT failures & pass rate
The 2017 SEAT Mii passed 89.4% of its 8,249 recorded MOT tests. All cars of a similar age fail 12.7% of the time, so this is 2.1pp better than the group it competes with. Failures cluster in visibility, lighting & signalling and tyres.
What the MOT record shows
No single area dominates — visibility (5.0%) and lighting & signalling (4.4%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are wipers, headlamp aim and pins and bushes — wipers alone was recorded 367 times.
Mileage is the strongest signal on the record: 7.1% of 0-30k cars fail, rising to 19.7% once past 90-120k — 2.8× the risk.
Tyres is the most common advisory, noted on 25.1% of tests — work that passed today but is likely due soon.
The trend is worsening — 7.8% of tests failed in 2021 against 13.9% in 2025, the usual pattern as a fleet ages.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Visibility | 5.0% | 409 |
| 2 | Lighting & signalling | 4.4% | 365 |
| 3 | Tyres | 3.3% | 274 |
| 4 | Brakes | 2.7% | 220 |
| 5 | Suspension | 1.9% | 155 |
| 6 | Body, structure & corrosion | 0.9% | 78 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Wipers | 367 |
| 2 | Headlamp aim | 250 |
| 3 | Pins and bushes | 145 |
| 4 | Washers | 133 |
| 5 | Service brake performance | 130 |
| 6 | Tread depth | 129 |
Top advisory categories
Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.
| # | Category | % of tests with advisory | Tests |
|---|---|---|---|
| 1 | Tyres | 25.1% | 2,072 |
| 2 | Brakes | 11.2% | 922 |
| 3 | Other defects | 5.7% | 469 |
| 4 | Suspension | 5.7% | 466 |
| 5 | Visibility | 2.3% | 190 |
| 6 | Emissions & environmental | 0.8% | 63 |
Failure rate by mileage
Higher-mileage cars tend to fail more — often the most useful guide to real condition.
| Mileage band | Tests | Fail rate |
|---|---|---|
| 0-30k | 3,996 | 7.1% |
| 30-60k | 3,434 | 13.0% |
| 60-90k | 718 | 17.5% |
| 90-120k | 71 | 19.7% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 1,630 | 7.8% |
| 2022 | 1,628 | 9.1% |
| 2023 | 1,620 | 9.1% |
| 2024 | 1,685 | 13.1% |
| 2025 | 1,686 | 13.9% |
What to check before buying a 2017 Mii
The failure pattern for this year is specific enough to inspect against: visibility accounted for 5.0% of tests. Start there.
- Visibility (5.0% of tests): Wipers, washers, mirrors and screen damage — usually inexpensive, but check for chips in the driver's line of sight. Typical repair: £15–£150.
- Lighting & signalling (4.4% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Tyres (3.3% of tests): Usually a quick, known-cost fix, but check tread, age and uneven wear (which can hint at alignment or suspension issues). Typical repair: £50–£120 per tyre.
Repair costs are rough UK ballpark ranges to set expectations, not quotes — actual prices vary widely by car, parts and garage.
Frequently asked questions
How many 2017 SEAT Miis pass their MOT?
89.4% of the 8,249 2017 SEAT Mii MOT tests in this dataset passed — a 10.6% fail rate.
What is the most common MOT failure on a 2017 SEAT Mii?
Visibility, recorded in 5.0% of tests, followed by lighting & signalling (4.4%).
Does the 2017 Mii get worse with mileage?
Its MOT fail rate rises from 7.1% in the 0-30k band to 19.7% in the 90-120k band.
Methodology & source. Based on 8,249 MOT tests. Dataset: DVSA MOT testing data (2021,2022,2023,2024,2025). Data last updated 2026-07-27. Figures reflect MOT-testable defects only — read the methodology for how these are calculated and what they don't measure.