2021 Toyota Prius — MOT failures & pass rate
Across 8,824 MOT tests, the 2021 Toyota Prius recorded a 93.9% pass rate. Small family cars of a similar age fail 7.3% of the time, so this is 1.2pp better than the group it competes with. Failures cluster in lighting & signalling, tyres and visibility.
What the MOT record shows
No single area dominates — lighting & signalling (4.1%) and tyres (3.1%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are tread depth, rear fog lamp and wipers — tread depth alone was recorded 150 times.
Mileage is the strongest signal on the record: 2.6% of 0-30k cars fail, rising to 13.7% once past 150k — 5.3× the risk.
Tyres is the most common advisory, noted on 12.4% of tests — work that passed today but is likely due soon.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 4.1% | 358 |
| 2 | Tyres | 3.1% | 274 |
| 3 | Visibility | 1.8% | 162 |
| 4 | Suspension | 0.9% | 77 |
| 5 | Brakes | 0.8% | 73 |
| 6 | Body, structure & corrosion | 0.2% | 19 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Tread depth | 150 |
| 2 | Rear fog lamp | 145 |
| 3 | Wipers | 130 |
| 4 | Headlamp aim | 113 |
| 5 | Registration plate lamp(s) | 80 |
| 6 | Position lamp | 67 |
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 | 12.4% | 1,093 |
| 2 | Brakes | 4.3% | 377 |
| 3 | Other defects | 2.1% | 183 |
| 4 | Suspension | 2.0% | 175 |
| 5 | Visibility | 1.6% | 145 |
| 6 | Lighting & signalling | 1.3% | 110 |
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 | 2,463 | 2.6% |
| 30-60k | 3,176 | 6.3% |
| 60-90k | 1,796 | 7.2% |
| 90-120k | 755 | 9.3% |
| 120-150k | 354 | 10.7% |
| 150k+ | 278 | 13.7% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 691 | 5.3% |
| 2022 | 1,036 | 7.8% |
| 2023 | 1,255 | 7.8% |
| 2024 | 2,498 | 6.0% |
| 2025 | 3,344 | 5.2% |
What to check before buying a 2021 Prius
The failure pattern for this year is specific enough to inspect against: lighting & signalling accounted for 4.1% of tests. Start there.
- Lighting & signalling (4.1% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Tyres (3.1% 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.
- Visibility (1.8% 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.
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 2021 Toyota Priuss pass their MOT?
93.9% of the 8,824 2021 Toyota Prius MOT tests in this dataset passed — a 6.1% fail rate.
What is the most common MOT failure on a 2021 Toyota Prius?
Lighting & signalling, recorded in 4.1% of tests, followed by tyres (3.1%).
Does the 2021 Prius get worse with mileage?
Its MOT fail rate rises from 2.6% in the 0-30k band to 13.7% in the 150k+ band.
Methodology & source. Based on 8,824 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.