2009 Mercedes-Benz CLS — MOT failures & pass rate
Across 7,611 MOT tests, the 2009 Mercedes-Benz CLS recorded a 75.9% pass rate. Executive cars of a similar age fail 21.7% of the time, so this is 2.4pp worse than the group it competes with. Failures cluster in suspension, lighting & signalling and brakes.
What the MOT record shows
No single area dominates — suspension (10.2%) and lighting & signalling (8.7%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are ball joint, rigid brake pipes and tread depth — ball joint alone was recorded 539 times.
A 150k+ example is materially riskier than a 0-30k one: 24.0% versus 17.3%.
Advisories point at the next bill rather than this one: brakes was flagged on 33.2% of tests without failing them.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Suspension | 10.2% | 773 |
| 2 | Lighting & signalling | 8.7% | 663 |
| 3 | Brakes | 8.1% | 617 |
| 4 | Tyres | 8.1% | 615 |
| 5 | Visibility | 4.3% | 330 |
| 6 | Steering | 2.9% | 223 |
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 | 539 |
| 2 | Rigid brake pipes | 497 |
| 3 | Tread depth | 327 |
| 4 | Coil spring | 327 |
| 5 | Headlamp aim | 277 |
| 6 | Washers | 238 |
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 | 33.2% | 2,524 |
| 2 | Tyres | 29.1% | 2,218 |
| 3 | Suspension | 22.6% | 1,717 |
| 4 | Emissions & environmental | 11.3% | 857 |
| 5 | Other defects | 10.2% | 778 |
| 6 | Body, structure & corrosion | 8.0% | 610 |
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 | 52 | 17.3% |
| 30-60k | 526 | 19.2% |
| 60-90k | 1,769 | 23.2% |
| 90-120k | 2,511 | 25.7% |
| 120-150k | 1,660 | 24.5% |
| 150k+ | 1,087 | 24.0% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Diesel | 7,258 | 24.3% |
| Petrol | 353 | 19.8% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 1,761 | 23.4% |
| 2022 | 1,698 | 24.3% |
| 2023 | 1,552 | 24.4% |
| 2024 | 1,422 | 25.1% |
| 2025 | 1,178 | 23.3% |
What to check before buying a 2009 CLS
On a 2009 CLS, suspension is what the MOT record says goes wrong most — it appeared in 10.2% of tests. Check these areas before you commit.
- Suspension (10.2% 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 (8.7% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Brakes (8.1% 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 CLSs pass their MOT?
75.9% of the 7,611 2009 Mercedes-Benz CLS MOT tests in this dataset passed — a 24.1% fail rate.
What is the most common MOT failure on a 2009 Mercedes-Benz CLS?
Suspension, recorded in 10.2% of tests, followed by lighting & signalling (8.7%).
Does the 2009 CLS get worse with mileage?
Its MOT fail rate rises from 17.3% in the 0-30k band to 24.0% in the 150k+ band.
Methodology & source. Based on 7,611 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.