2003 Mercedes-Benz C-Class — MOT failures & pass rate
Across 39,827 MOT tests analysed for the 2003 Mercedes-Benz C-Class, the most common recorded failure areas were suspension, lighting & signalling and brakes. Its pass rate of 72.4% was below the average for executive cars of a similar age (75.3%). Higher-mileage examples failed more often — 30.8% in the 150k+ group versus 13.7% in the 0-30k group.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Suspension | 16.8% | 6,700 |
| 2 | Lighting & signalling | 12.3% | 4,912 |
| 3 | Brakes | 8.4% | 3,339 |
| 4 | Emissions & environmental | 7.9% | 3,150 |
| 5 | Visibility | 5.9% | 2,369 |
| 6 | Tyres | 5.7% | 2,286 |
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 | 3,028 |
| 2 | Coil spring | 2,896 |
| 3 | Catalyst emissions | 2,871 |
| 4 | Headlamp aim | 2,692 |
| 5 | Headlamp | 1,891 |
| 6 | Tread depth | 1,662 |
Top advisory categories
Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.
| # | Category | % of tests with advisory | Tests |
|---|---|---|---|
| 1 | Suspension | 39.9% | 15,901 |
| 2 | Brakes | 37.4% | 14,895 |
| 3 | Tyres | 26.8% | 10,685 |
| 4 | Lighting & signalling | 17.9% | 7,119 |
| 5 | Other defects | 14.3% | 5,704 |
| 6 | Emissions & environmental | 11.0% | 4,367 |
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 | 386 | 13.7% |
| 30-60k | 3,565 | 21.1% |
| 60-90k | 8,650 | 25.5% |
| 90-120k | 11,667 | 28.2% |
| 120-150k | 8,611 | 29.3% |
| 150k+ | 6,781 | 30.8% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Petrol | 27,444 | 27.3% |
| Diesel | 12,380 | 28.2% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 12,084 | 28.3% |
| 2022 | 9,497 | 27.3% |
| 2023 | 7,659 | 27.5% |
| 2024 | 6,010 | 27.3% |
| 2025 | 4,577 | 26.6% |
What to check before buying a 2003 C-Class
Before buying a 2003 Mercedes-Benz C-Class, focus on the areas it most often fails on. Suspension accounted for 16.8% of tests for this year.
- Suspension (16.8% 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.
- Lighting & signalling (12.3% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Brakes (8.4% 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 2003 Mercedes-Benz C-Classs pass their MOT?
72.4% of the 39,827 2003 Mercedes-Benz C-Class MOT tests in this dataset passed — a 27.6% fail rate.
What is the most common MOT failure on a 2003 Mercedes-Benz C-Class?
Suspension, recorded in 16.8% of tests, followed by lighting & signalling (12.3%).
Does the 2003 C-Class get worse with mileage?
Its MOT fail rate rises from 13.7% in the 0-30k band to 30.8% in the 150k+ band.
Methodology & source. Based on 39,827 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.