2020 Mercedes-Benz CLS — MOT failures & pass rate
Across 1,012 MOT tests, the 2020 Mercedes-Benz CLS recorded an 83.3% pass rate. That is 6.7 percentage points worse than executive cars of a similar age, which fail at 10.0%. Failures cluster in tyres, road wheels and suspension.
What the MOT record shows
No single area dominates — tyres (10.1%) and road wheels (7.8%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are tread depth, ball joint and registration plates — tread depth alone was recorded 18 times.
Mileage matters less than usual here: the 2020 CLS fails 16.2% of the time in the 0-30k band and 15.7% at 60-90k, a spread of only 0.5 points.
Tyres is the most common advisory, noted on 16.0% of tests — work that passed today but is likely due soon.
The trend is improving — the fail rate fell from 18.2% in 2023 to 15.4% in 2025, as the worst-kept examples leave the fleet.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 10.1% | 102 |
| 2 | Road wheels | 7.8% | 79 |
| 3 | Suspension | 1.0% | 10 |
| 4 | Lighting & signalling | 0.7% | 7 |
| 5 | Brakes | 0.7% | 7 |
| 6 | Visibility | 0.6% | 6 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Tread depth | 18 |
| 2 | Ball joint | 10 |
| 3 | Registration plates | 9 |
| 4 | Brake pads | 9 |
| 5 | Headlamp aim | 5 |
| 6 | Wipers | 5 |
Top advisory categories
Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.
| # | Category | % of tests with advisory | Tests |
|---|---|---|---|
| 1 | Tyres | 16.0% | 162 |
| 2 | Brakes | 8.0% | 81 |
| 3 | Suspension | 3.9% | 39 |
| 4 | Other defects | 3.5% | 35 |
| 5 | Visibility | 2.8% | 28 |
| 6 | Road wheels | 2.5% | 25 |
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 | 482 | 16.2% |
| 30-60k | 424 | 17.4% |
| 60-90k | 89 | 15.7% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Diesel | 839 | 17.4% |
| Hybrid | 167 | 13.8% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2023 | 340 | 18.2% |
| 2024 | 338 | 16.9% |
| 2025 | 319 | 15.4% |
What to check before buying a 2020 CLS
The failure pattern for this year is specific enough to inspect against: tyres accounted for 10.1% of tests. Start there.
- Tyres (10.1% of tests): Usually a quick, known-cost fix, but check tread, age and uneven wear (which can hint at alignment or suspension issues). Typical repair: £50–£120 per tyre.
- Road wheels (7.8% of tests): Damaged or corroded wheels, missing/loose fixings — generally a moderate fix. Typical repair: £80–£250.
- Suspension (1.0% 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.
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 2020 Mercedes-Benz CLSs pass their MOT?
83.3% of the 1,012 2020 Mercedes-Benz CLS MOT tests in this dataset passed — a 16.7% fail rate.
What is the most common MOT failure on a 2020 Mercedes-Benz CLS?
Tyres, recorded in 10.1% of tests, followed by road wheels (7.8%).
Does the 2020 CLS get worse with mileage?
Its MOT fail rate rises from 16.2% in the 0-30k band to 15.7% in the 60-90k band.
Methodology & source. Based on 1,012 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.