2018 BMW i3 — MOT failures & pass rate
The 2018 BMW i3 passed 92.1% of its 16,712 recorded MOT tests. That is 2.5 percentage points better than small family cars of a similar age, which fail at 10.4%. Failures cluster in tyres, lighting & signalling and visibility.
What the MOT record shows
Tyres dominates the failure mix at 5.3% of all tests — 3.1 points clear of lighting & signalling, so it is the first thing to check.
At component level the recurring items are tread depth, headlamp aim and washers — tread depth alone was recorded 466 times.
Mileage matters less than usual here: the 2018 i3 fails 6.3% of the time in the 0-30k band and 8.6% at 120-150k, a spread of only 2.3 points.
Fuel type barely separates them — electric fails 7.8% of the time against 8.0% for hybrid.
Advisories point at the next bill rather than this one: tyres was flagged on 24.0% of tests without failing them.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 5.3% | 886 |
| 2 | Lighting & signalling | 2.2% | 374 |
| 3 | Visibility | 1.7% | 291 |
| 4 | Suspension | 0.5% | 90 |
| 5 | Brakes | 0.5% | 89 |
| 6 | Road wheels | 0.3% | 48 |
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 | 466 |
| 2 | Headlamp aim | 428 |
| 3 | Washers | 227 |
| 4 | Wipers | 99 |
| 5 | Side repeaters | 56 |
| 6 | Registration plates | 53 |
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 | 24.0% | 4,007 |
| 2 | Brakes | 6.4% | 1,073 |
| 3 | Other defects | 4.5% | 747 |
| 4 | Visibility | 2.5% | 418 |
| 5 | Road wheels | 2.2% | 366 |
| 6 | Suspension | 1.0% | 173 |
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 | 8,409 | 6.3% |
| 30-60k | 6,430 | 9.1% |
| 60-90k | 1,608 | 10.7% |
| 90-120k | 217 | 12.4% |
| 120-150k | 35 | 8.6% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Hybrid | 10,665 | 8.0% |
| Electric | 6,047 | 7.8% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 3,416 | 7.4% |
| 2022 | 3,327 | 6.8% |
| 2023 | 3,291 | 7.6% |
| 2024 | 3,323 | 9.1% |
| 2025 | 3,355 | 8.6% |
What to check before buying a 2018 i3
On a 2018 i3, tyres is what the MOT record says goes wrong most — it appeared in 5.3% of tests. Check these areas before you commit.
- Tyres (5.3% 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.
- Lighting & signalling (2.2% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Visibility (1.7% 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 2018 BMW i3s pass their MOT?
92.1% of the 16,712 2018 BMW i3 MOT tests in this dataset passed — a 7.9% fail rate.
What is the most common MOT failure on a 2018 BMW i3?
Tyres, recorded in 5.3% of tests, followed by lighting & signalling (2.2%).
Does the 2018 i3 get worse with mileage?
Its MOT fail rate rises from 6.3% in the 0-30k band to 8.6% in the 120-150k band.
Methodology & source. Based on 16,712 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.