2021 Bmw M135I Auto — MOT failures & pass rate
Across 7,548 MOT tests analysed for the 2021 Bmw M135I Auto, the most common recorded failure areas were tyres, lighting & signalling and brakes. Its pass rate of 92.3% was above the average for cars of a similar age (91.3%).
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 5.6% | 424 |
| 2 | Lighting & signalling | 1.3% | 101 |
| 3 | Brakes | 0.6% | 48 |
| 4 | Visibility | 0.5% | 40 |
| 5 | Suspension | 0.4% | 33 |
| 6 | Other defects | 0.3% | 22 |
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 | 166 |
| 2 | Headlamp aim | 72 |
| 3 | Registration plates | 38 |
| 4 | Brake pads | 38 |
| 5 | Horn | 34 |
| 6 | Wipers | 22 |
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 | 18.1% | 1,370 |
| 2 | Brakes | 6.6% | 498 |
| 3 | Other defects | 3.8% | 284 |
| 4 | Visibility | 1.8% | 135 |
| 5 | Suspension | 0.4% | 33 |
| 6 | Emissions & environmental | 0.2% | 17 |
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 | 4,590 | 7.0% |
| 30-60k | 2,819 | 8.8% |
| 60-90k | 127 | 5.5% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2023 | 353 | 3.7% |
| 2024 | 3,670 | 8.7% |
| 2025 | 3,521 | 7.0% |
What to check before buying a 2021 M135I Auto
Before buying a 2021 Bmw M135I Auto, focus on the areas it most often fails on. Tyres accounted for 5.6% of tests for this year.
- Tyres (5.6% 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.
- Lighting & signalling (1.3% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Brakes (0.6% of tests): Pads/discs are routine wear; binding, imbalance or corroded pipes are more serious — test for pulling under braking. Typical repair: £100–£350 per axle.
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 Bmw M135I Autos pass their MOT?
92.3% of the 7,548 2021 Bmw M135I Auto MOT tests in this dataset passed — a 7.7% fail rate.
What is the most common MOT failure on a 2021 Bmw M135I Auto?
Tyres, recorded in 5.6% of tests, followed by lighting & signalling (1.3%).
Does the 2021 M135I Auto get worse with mileage?
Its MOT fail rate rises from 7.0% in the 0-30k band to 5.5% in the 60-90k band.
Methodology & source. Based on 7,548 MOT tests. Dataset: DVSA MOT testing data (2021,2022,2023,2024,2025). Data last updated 2026-07-01. Figures reflect MOT-testable defects only — read the methodology for how these are calculated and what they don't measure.