2021 BMW i3 — MOT failures & pass rate
The 2021 BMW i3 passed 93.1% of its 7,619 recorded MOT tests. Against small family cars of a similar age (8.3% fail rate), the 2021 i3 comes out 1.4pp better. Failures cluster in tyres, lighting & signalling and visibility.
What the MOT record shows
No single area dominates — tyres (4.8%) and lighting & signalling (3.9%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are headlamp aim, tread depth and washers — headlamp aim alone was recorded 380 times.
Condition tracks the odometer closely. Failures run at 6.5% in the 0-30k band and 10.8% in the 60-90k band, a 4.3-point spread.
Advisories point at the next bill rather than this one: tyres was flagged on 22.7% of tests without failing them.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 4.8% | 364 |
| 2 | Lighting & signalling | 3.9% | 298 |
| 3 | Visibility | 1.5% | 113 |
| 4 | Road wheels | 0.3% | 25 |
| 5 | Seat belts & restraints | 0.2% | 17 |
| 6 | Suspension | 0.2% | 12 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Headlamp aim | 380 |
| 2 | Tread depth | 157 |
| 3 | Washers | 89 |
| 4 | Side repeaters | 53 |
| 5 | Wipers | 30 |
| 6 | Size/type | 20 |
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 | 22.7% | 1,730 |
| 2 | Other defects | 4.3% | 326 |
| 3 | Brakes | 2.9% | 218 |
| 4 | Road wheels | 2.5% | 187 |
| 5 | Visibility | 1.6% | 119 |
| 6 | Suspension | 0.4% | 28 |
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 | 5,919 | 6.5% |
| 30-60k | 1,591 | 8.0% |
| 60-90k | 102 | 10.8% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2023 | 196 | 5.6% |
| 2024 | 3,728 | 7.9% |
| 2025 | 3,694 | 5.9% |
What to check before buying a 2021 i3
On a 2021 i3, tyres is what the MOT record says goes wrong most — it appeared in 4.8% of tests. Check these areas before you commit.
- Tyres (4.8% 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 (3.9% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Visibility (1.5% 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 BMW i3s pass their MOT?
93.1% of the 7,619 2021 BMW i3 MOT tests in this dataset passed — a 6.9% fail rate.
What is the most common MOT failure on a 2021 BMW i3?
Tyres, recorded in 4.8% of tests, followed by lighting & signalling (3.9%).
Does the 2021 i3 get worse with mileage?
Its MOT fail rate rises from 6.5% in the 0-30k band to 10.8% in the 60-90k band.
Methodology & source. Based on 7,619 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.