Mercedes-Benz Cl MOT pass rate & common failures
Across 38 model years and 8,129 tests, the Mercedes-Benz Cl passes its MOT 83.4% of the time. Coupes & convertibles of a similar age fail 20.0% of the time, so this is 3.4pp better than the group it competes with. Its most common failure areas are brakes, suspension and lighting & signalling.
What the MOT record shows
No single area dominates — brakes (6.5%) and suspension (5.9%) 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 headlamp aim — ball joint alone was recorded 238 times.
Mileage is the strongest signal on the record: 10.1% of 0-30k cars fail, rising to 22.3% once past 150k — 2.2× the risk.
Advisories point at the next bill rather than this one: brakes was flagged on 26.3% of tests without failing them.
The trend is improving — the fail rate fell from 17.9% in 2021 to 15.6% in 2025, as the worst-kept examples leave the fleet.
How it compares
By model year
Every Cl model year with a usable sample. Years with their own detailed report are linked.
| Year | Tests | Pass rate | Fail rate | Most common failure |
|---|---|---|---|---|
| 1996 | 52 | 80.8% | 19.2% | Brakes |
| 1997 | 210 | 88.1% | 11.9% | Lighting & signalling |
| 1998 | 212 | 84.0% | 16.0% | Brakes |
| 1999 | 32 | 81.3% | 18.8% | Brakes |
| 2000 | 211 | 82.5% | 17.5% | Lighting & signalling |
| 2001 | 398 | 82.2% | 17.8% | Lighting & signalling |
| 2002 | 891 | 80.7% | 19.3% | Lighting & signalling |
| 2003 | 790 | 82.2% | 17.8% | Lighting & signalling |
| 2004 | 407 | 84.5% | 15.5% | Lighting & signalling |
| 2005 | 245 | 86.5% | 13.5% | Suspension |
| 2006 | 177 | 84.8% | 15.3% | Brakes |
| 2007 | 1,311 | 83.7% | 16.3% | Brakes |
| 2008 | 573 | 84.3% | 15.7% | Brakes |
| 2009 | 296 | 80.4% | 19.6% | Brakes |
| 2010 | 326 | 81.9% | 18.1% | Brakes |
| 2011 | 305 | 83.6% | 16.4% | Brakes |
| 2012 | 382 | 84.5% | 15.4% | Brakes |
| 2013 | 628 | 83.4% | 16.6% | Tyres |
| 2014 | 540 | 86.1% | 13.9% | Brakes |
Most common failures (all years)
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Brakes | 6.5% | 530 |
| 2 | Suspension | 5.9% | 480 |
| 3 | Lighting & signalling | 5.1% | 418 |
| 4 | Tyres | 4.6% | 373 |
| 5 | Emissions & environmental | 2.7% | 220 |
| 6 | Visibility | 2.4% | 194 |
| 7 | Seat belts & restraints | 1.0% | 78 |
| 8 | Body, structure & corrosion | 0.9% | 76 |
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 | 238 |
| 2 | Rigid brake pipes | 193 |
| 3 | Headlamp aim | 184 |
| 4 | Rbt (sp) | 183 |
| 5 | Tread depth | 160 |
| 6 | Shock absorbers | 131 |
| 7 | Catalyst emissions | 128 |
| 8 | Malfunction indicator lamp | 119 |
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 | 26.3% | 2,139 |
| 2 | Suspension | 20.0% | 1,623 |
| 3 | Tyres | 19.6% | 1,595 |
| 4 | Emissions & environmental | 6.7% | 544 |
| 5 | Other defects | 5.1% | 416 |
| 6 | Lighting & signalling | 4.3% | 354 |
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 | 385 | 10.1% |
| 30-60k | 1,594 | 13.0% |
| 60-90k | 2,679 | 16.9% |
| 90-120k | 2,083 | 17.7% |
| 120-150k | 975 | 19.1% |
| 150k+ | 403 | 22.3% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Petrol | 8,078 | 16.5% |
| Diesel | 51 | 21.6% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 1,808 | 17.9% |
| 2022 | 1,709 | 15.6% |
| 2023 | 1,663 | 17.1% |
| 2024 | 1,542 | 16.5% |
| 2025 | 1,407 | 15.6% |
What to check before buying a Mercedes-Benz Cl
- Brakes (6.5% 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.
- Suspension (5.9% 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 (5.1% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
Repair costs are rough UK ballpark ranges to set expectations, not quotes — actual prices vary widely by car, parts and garage.
Frequently asked questions
What is the MOT pass rate for the Mercedes-Benz Cl?
83.4% of the 8,129 Mercedes-Benz Cl MOT tests in this dataset passed, a 16.6% fail rate, across model years 1986–2023.
What does the Mercedes-Benz Cl most often fail its MOT on?
Brakes, recorded in 6.5% of tests, then suspension (5.9%).
How much does mileage affect Cl MOT results?
Fail rates run at 10.1% for cars in the 0-30k band and 22.3% for 150k+, a 12.2-point difference.
Methodology & source. Based on 8,129 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.