2015 Smart Forfour — MOT failures & pass rate
The 2015 Smart Forfour passed 81.3% of its 33,233 recorded MOT tests. Against city cars of a similar age (15.6% fail rate), the 2015 Forfour comes out 3.1pp worse. Failures cluster in lighting & signalling, suspension and tyres.
What the MOT record shows
No single area dominates — lighting & signalling (7.0%) and suspension (6.8%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are stop lamp, tread depth and ball joint — stop lamp alone was recorded 1,544 times.
Mileage is the strongest signal on the record: 12.0% of 0-30k cars fail, rising to 20.0% once past 150k.
Tyres is the most common advisory, noted on 27.1% of tests — work that passed today but is likely due soon.
The trend is worsening — 14.3% of tests failed in 2021 against 22.0% in 2025, the usual pattern as a fleet ages.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 7.0% | 2,326 |
| 2 | Suspension | 6.8% | 2,272 |
| 3 | Tyres | 6.8% | 2,258 |
| 4 | Visibility | 5.2% | 1,742 |
| 5 | Emissions & environmental | 4.1% | 1,356 |
| 6 | Brakes | 2.9% | 982 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Stop lamp | 1,544 |
| 2 | Tread depth | 1,457 |
| 3 | Ball joint | 1,405 |
| 4 | Catalyst emissions | 1,209 |
| 5 | Wipers | 1,109 |
| 6 | Washers | 886 |
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 | 27.1% | 9,017 |
| 2 | Brakes | 17.8% | 5,906 |
| 3 | Suspension | 8.3% | 2,765 |
| 4 | Other defects | 5.7% | 1,878 |
| 5 | Visibility | 3.3% | 1,079 |
| 6 | Emissions & environmental | 2.7% | 909 |
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 | 7,069 | 12.0% |
| 30-60k | 18,611 | 18.6% |
| 60-90k | 6,345 | 24.6% |
| 90-120k | 1,034 | 26.5% |
| 120-150k | 136 | 27.9% |
| 150k+ | 30 | 20.0% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 6,400 | 14.3% |
| 2022 | 6,587 | 16.7% |
| 2023 | 6,720 | 19.1% |
| 2024 | 6,757 | 20.9% |
| 2025 | 6,769 | 22.0% |
What to check before buying a 2015 Forfour
The failure pattern for this year is specific enough to inspect against: lighting & signalling accounted for 7.0% of tests. Start there.
- Lighting & signalling (7.0% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Suspension (6.8% 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.
- Tyres (6.8% 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.
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 2015 Smart Forfours pass their MOT?
81.3% of the 33,233 2015 Smart Forfour MOT tests in this dataset passed — a 18.6% fail rate.
What is the most common MOT failure on a 2015 Smart Forfour?
Lighting & signalling, recorded in 7.0% of tests, followed by suspension (6.8%).
Does the 2015 Forfour get worse with mileage?
Its MOT fail rate rises from 12.0% in the 0-30k band to 20.0% in the 150k+ band.
Methodology & source. Based on 33,233 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.