2009 Mercedes-Benz C-Class — MOT failures & pass rate
Across 93,481 MOT tests analysed for the 2009 Mercedes-Benz C-Class, the most common recorded failure areas were suspension, lighting & signalling and brakes. Its pass rate of 76.6% was below the average for executive cars of a similar age (78.2%). Higher-mileage examples failed more often — 26.2% in the 150k+ group versus 11.0% in the 0-30k group.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Suspension | 13.7% | 12,772 |
| 2 | Lighting & signalling | 9.7% | 9,064 |
| 3 | Brakes | 8.9% | 8,278 |
| 4 | Tyres | 6.2% | 5,831 |
| 5 | Emissions & environmental | 3.2% | 3,001 |
| 6 | Visibility | 2.7% | 2,518 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Ball joint | 7,411 |
| 2 | Rigid brake pipes | 6,186 |
| 3 | Tread depth | 3,923 |
| 4 | Headlamp aim | 3,740 |
| 5 | Position lamp | 3,307 |
| 6 | Coil spring | 3,209 |
Top advisory categories
Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.
| # | Category | % of tests with advisory | Tests |
|---|---|---|---|
| 1 | Brakes | 35.9% | 33,550 |
| 2 | Tyres | 27.0% | 25,256 |
| 3 | Suspension | 27.0% | 25,220 |
| 4 | Other defects | 7.6% | 7,103 |
| 5 | Lighting & signalling | 7.3% | 6,828 |
| 6 | Emissions & environmental | 6.0% | 5,657 |
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 | 799 | 11.0% |
| 30-60k | 6,776 | 15.2% |
| 60-90k | 19,726 | 20.8% |
| 90-120k | 28,322 | 23.9% |
| 120-150k | 21,963 | 25.9% |
| 150k+ | 15,794 | 26.2% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Diesel | 61,264 | 24.5% |
| Petrol | 32,217 | 21.2% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 20,925 | 22.6% |
| 2022 | 20,131 | 22.8% |
| 2023 | 19,139 | 23.8% |
| 2024 | 17,545 | 24.2% |
| 2025 | 15,741 | 23.6% |
What to check before buying a 2009 C-Class
Before buying a 2009 Mercedes-Benz C-Class, focus on the areas it most often fails on. Suspension accounted for 13.7% of tests for this year.
- Suspension (13.7% 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 (9.7% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Brakes (8.9% 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 many 2009 Mercedes-Benz C-Classs pass their MOT?
76.6% of the 93,481 2009 Mercedes-Benz C-Class MOT tests in this dataset passed — a 23.4% fail rate.
What is the most common MOT failure on a 2009 Mercedes-Benz C-Class?
Suspension, recorded in 13.7% of tests, followed by lighting & signalling (9.7%).
Does the 2009 C-Class get worse with mileage?
Its MOT fail rate rises from 11.0% in the 0-30k band to 26.2% in the 150k+ band.
Methodology & source. Based on 93,481 MOT tests. Dataset: DVSA MOT testing data (2021,2022,2023,2024,2025). Data last updated 2026-07-01. Figures reflect MOT-testable defects only — read the methodology for how these are calculated and what they don't measure.