Mercedes-Benz Cl 500 MOT pass rate & common failures
10,990 MOT tests on the Mercedes-Benz Cl 500 (1996–2016) give it an 82.0% pass rate. All cars of a similar age fail 26.6% of the time, so this is 8.6pp better than the group it competes with. Its most common failure areas are suspension, lighting & signalling and brakes.
What the MOT record shows
No single area dominates — suspension (7.3%) and lighting & signalling (6.8%) 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 shock absorbers — ball joint alone was recorded 387 times.
Mileage is the strongest signal on the record: 10.1% of 0-30k cars fail, rising to 20.7% once past 150k — 2.0× the risk.
Advisories point at the next bill rather than this one: brakes was flagged on 29.0% of tests without failing them.
The trend is improving — the fail rate fell from 19.2% in 2021 to 17.3% in 2025, as the worst-kept examples leave the fleet.
How it compares
By model year
Every Cl 500 model year with a usable sample. Years with their own detailed report are linked.
| Year | Tests | Pass rate | Fail rate | Most common failure |
|---|---|---|---|---|
| 1997 | 73 | 87.7% | 12.3% | Lighting & signalling |
| 1998 | 110 | 80.0% | 20.0% | Lighting & signalling |
| 2000 | 965 | 77.1% | 22.9% | Suspension |
| 2001 | 968 | 81.4% | 18.6% | Lighting & signalling |
| 2002 | 1,479 | 80.2% | 19.8% | Lighting & signalling |
| 2003 | 1,050 | 80.8% | 19.2% | Suspension |
| 2004 | 885 | 84.2% | 15.8% | Suspension |
| 2005 | 924 | 83.1% | 16.9% | Lighting & signalling |
| 2006 | 301 | 80.7% | 19.3% | Lighting & signalling |
| 2007 | 1,310 | 83.9% | 16.1% | Brakes |
| 2008 | 779 | 83.3% | 16.7% | Brakes |
| 2009 | 879 | 83.0% | 17.0% | Brakes |
| 2010 | 600 | 84.2% | 15.8% | Brakes |
| 2011 | 366 | 84.2% | 15.8% | Suspension |
| 2012 | 221 | 83.3% | 16.7% | Tyres |
Most common failures (all years)
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Suspension | 7.3% | 806 |
| 2 | Lighting & signalling | 6.8% | 750 |
| 3 | Brakes | 6.3% | 694 |
| 4 | Tyres | 4.5% | 491 |
| 5 | Visibility | 2.6% | 287 |
| 6 | Emissions & environmental | 2.1% | 228 |
| 7 | Body, structure & corrosion | 1.8% | 195 |
| 8 | Seat belts & restraints | 1.6% | 178 |
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 | 387 |
| 2 | Rigid brake pipes | 352 |
| 3 | Shock absorbers | 283 |
| 4 | Tread depth | 282 |
| 5 | Headlamp aim | 248 |
| 6 | Position lamp | 231 |
| 7 | Pins and bushes | 206 |
| 8 | Individual direction indicators | 184 |
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 | 29.0% | 3,191 |
| 2 | Suspension | 24.6% | 2,704 |
| 3 | Tyres | 21.6% | 2,370 |
| 4 | Emissions & environmental | 8.7% | 957 |
| 5 | Lighting & signalling | 7.8% | 857 |
| 6 | Body, structure & corrosion | 7.0% | 767 |
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 | 276 | 10.1% |
| 30-60k | 1,404 | 13.3% |
| 60-90k | 3,202 | 17.4% |
| 90-120k | 3,356 | 18.4% |
| 120-150k | 1,946 | 21.1% |
| 150k+ | 762 | 20.7% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 2,680 | 19.2% |
| 2022 | 2,357 | 18.2% |
| 2023 | 2,188 | 17.3% |
| 2024 | 1,964 | 17.2% |
| 2025 | 1,801 | 17.3% |
What to check before buying a Mercedes-Benz Cl 500
- Suspension (7.3% 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 (6.8% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Brakes (6.3% 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
What is the MOT pass rate for the Mercedes-Benz Cl 500?
82.0% of the 10,990 Mercedes-Benz Cl 500 MOT tests in this dataset passed, a 17.9% fail rate, across model years 1996–2016.
What does the Mercedes-Benz Cl 500 most often fail its MOT on?
Suspension, recorded in 7.3% of tests, then lighting & signalling (6.8%).
How much does mileage affect Cl 500 MOT results?
Fail rates run at 10.1% for cars in the 0-30k band and 20.7% for 150k+, a 10.6-point difference.
Methodology & source. Based on 10,990 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.