2015 Mercedes-Benz C-Class — MOT failures & pass rate
203,661 MOT tests on the 2015 Mercedes-Benz C-Class are in this dataset, and 85.8% of them passed. That is effectively the same as executive cars of a similar age (14.1% fail rate), so the MOT record here is unremarkable in either direction. Failures cluster in tyres, suspension and emissions & environmental.
What the MOT record shows
No single area dominates — tyres (6.6%) and suspension (5.0%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are tread depth, ball joint and malfunction indicator lamp — tread depth alone was recorded 9,909 times.
A 150k+ example is materially riskier than a 0-30k one: 17.1% versus 7.8%.
The hybrid cars hold up better: 11.5% fail against 14.9% for diesel, a 3.4-point gap across 164,290 tests.
Tyres is the most common advisory, noted on 25.1% of tests — work that passed today but is likely due soon.
The trend is worsening — 12.2% of tests failed in 2021 against 15.8% in 2025, the usual pattern as a fleet ages.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 6.6% | 13,443 |
| 2 | Suspension | 5.0% | 10,184 |
| 3 | Emissions & environmental | 2.9% | 5,927 |
| 4 | Brakes | 2.6% | 5,357 |
| 5 | Lighting & signalling | 2.3% | 4,725 |
| 6 | Visibility | 1.7% | 3,407 |
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 | 9,909 |
| 2 | Ball joint | 6,053 |
| 3 | Malfunction indicator lamp | 5,535 |
| 4 | Coil spring | 4,631 |
| 5 | Headlamp aim | 3,883 |
| 6 | Brake pads | 3,612 |
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 | 25.1% | 51,035 |
| 2 | Brakes | 17.1% | 34,874 |
| 3 | Suspension | 8.8% | 17,946 |
| 4 | Other defects | 5.8% | 11,731 |
| 5 | Visibility | 3.6% | 7,372 |
| 6 | Emissions & environmental | 1.2% | 2,438 |
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 | 8,864 | 7.8% |
| 30-60k | 60,427 | 11.7% |
| 60-90k | 71,110 | 14.9% |
| 90-120k | 39,543 | 16.9% |
| 120-150k | 15,834 | 16.3% |
| 150k+ | 7,817 | 17.1% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Diesel | 161,354 | 14.9% |
| Petrol | 39,358 | 11.8% |
| Hybrid | 2,936 | 11.5% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 41,160 | 12.2% |
| 2022 | 41,014 | 13.2% |
| 2023 | 41,068 | 14.5% |
| 2024 | 40,599 | 15.5% |
| 2025 | 39,820 | 15.8% |
What to check before buying a 2015 C-Class
The failure pattern for this year is specific enough to inspect against: tyres accounted for 6.6% of tests. Start there.
- Tyres (6.6% 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.
- Suspension (5.0% 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.
- Emissions & environmental (2.9% of tests): More common on older diesels (DPF/EGR) — can be expensive; check for warning lights and smoke. Typical repair: £100–£600.
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 Mercedes-Benz C-Classs pass their MOT?
85.8% of the 203,661 2015 Mercedes-Benz C-Class MOT tests in this dataset passed — a 14.2% fail rate.
What is the most common MOT failure on a 2015 Mercedes-Benz C-Class?
Tyres, recorded in 6.6% of tests, followed by suspension (5.0%).
Does the 2015 C-Class get worse with mileage?
Its MOT fail rate rises from 7.8% in the 0-30k band to 17.1% in the 150k+ band.
Methodology & source. Based on 203,661 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.