BMW 645i — MOT pass rate & failures
The BMW 645i recorded a 78.6% MOT pass rate across 10,689 tests in this dataset (model years 1988–2019), with suspension, lighting & signalling and brakes its most common failure areas. Its 21.4% fail rate is higher than the 15.5% average across all BMW 6 Series versions.
How it compares
By model year
| Year | Tests | Pass rate | Fail rate |
|---|---|---|---|
| 2003 | 118 | 77.1% | 22.9% |
| 2004 | 7,140 | 78.3% | 21.6% |
| 2005 | 3,230 | 79.3% | 20.7% |
| 2011 | 155 | 77.4% | 22.6% |
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Suspension | 10.5% | 1,126 |
| 2 | Lighting & signalling | 8.5% | 904 |
| 3 | Brakes | 6.8% | 729 |
| 4 | Tyres | 4.4% | 473 |
| 5 | Emissions & environmental | 4.4% | 474 |
| 6 | Visibility | 3.7% | 391 |
| 7 | Seat belts & restraints | 2.5% | 266 |
| 8 | Steering | 2.1% | 227 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Rigid brake pipes | 468 |
| 2 | Coil spring | 433 |
| 3 | Pins and bushes | 414 |
| 4 | Position lamp | 355 |
| 5 | Ball joint | 346 |
| 6 | Linkage ball joint dust cover | 343 |
Top advisory categories
Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.
| # | Category | % of tests with advisory | Tests |
|---|---|---|---|
| 1 | Emissions & environmental | 30.0% | 3,202 |
| 2 | Brakes | 29.5% | 3,151 |
| 3 | Suspension | 25.5% | 2,729 |
| 4 | Tyres | 23.6% | 2,528 |
| 5 | Other defects | 8.5% | 910 |
| 6 | Lighting & signalling | 4.9% | 528 |
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 | 143 | 10.5% |
| 30-60k | 902 | 15.6% |
| 60-90k | 2,636 | 20.7% |
| 90-120k | 3,780 | 22.2% |
| 120-150k | 2,300 | 22.9% |
| 150k+ | 922 | 23.9% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 2,559 | 23.0% |
| 2022 | 2,340 | 20.9% |
| 2023 | 2,185 | 22.1% |
| 2024 | 1,868 | 19.2% |
| 2025 | 1,737 | 21.1% |
What to check before buying a BMW 645i
Focus on the areas it most often fails on — and remember MOT data covers testable defects only, not engine or gearbox health.
- Suspension (10.5% of tests): Worn drop links, bushes, springs or shocks — listen for knocks over bumps and check for uneven tyre wear. Typical repair: £150–£450 per corner.
- Lighting & signalling (8.5% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Brakes (6.8% 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 reliable is the BMW 645i at MOT time?
78.6% of the 10,689 BMW 645i MOT tests in this dataset passed — a 21.4% fail rate, worse than the 15.5% average across all 6 Series versions.
What is the most common MOT failure on a BMW 645i?
Suspension, recorded in 10.5% of tests, followed by lighting & signalling (8.5%).
Does the 645i get worse with mileage?
Its MOT fail rate rises from 10.5% in the 0-30k band to 23.9% in the 150k+ band.
Methodology & source. Based on 10,689 MOT tests. Dataset: DVSA MOT testing data (2021,2022,2023,2024,2025). Data last updated 2026-07-06. Figures reflect MOT-testable defects only — read the methodology for how these are calculated and what they don't measure.