2020 Mercedes-Benz SLC — MOT failures & pass rate
1,915 MOT tests on the 2020 Mercedes-Benz SLC are in this dataset, and 93.0% of them passed. That is 1.2 percentage points better than coupes & convertibles of a similar age, which fail at 8.2%. Failures cluster in tyres, lighting & signalling and suspension.
What the MOT record shows
One area stands out: tyres, recorded in 5.3% of tests against 1.4% for the next-worst category.
At component level the recurring items are headlamp aim, tread depth and registration plates — headlamp aim alone was recorded 24 times.
Tyres is the most common advisory, noted on 18.1% of tests — work that passed today but is likely due soon.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 5.3% | 102 |
| 2 | Lighting & signalling | 1.4% | 26 |
| 3 | Suspension | 0.7% | 13 |
| 4 | Emissions & environmental | 0.5% | 10 |
| 5 | Road wheels | 0.5% | 9 |
| 6 | Brakes | 0.5% | 9 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Headlamp aim | 24 |
| 2 | Tread depth | 18 |
| 3 | Registration plates | 8 |
| 4 | Catalyst emissions | 6 |
| 5 | Brake pads | 5 |
| 6 | Headlamp | 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 | 18.1% | 347 |
| 2 | Brakes | 2.5% | 48 |
| 3 | Visibility | 1.9% | 37 |
| 4 | Other defects | 1.9% | 36 |
| 5 | Suspension | 1.6% | 30 |
| 6 | Road wheels | 1.5% | 28 |
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 | 1,610 | 6.0% |
| 30-60k | 287 | 11.8% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2023 | 635 | 6.6% |
| 2024 | 618 | 6.6% |
| 2025 | 648 | 7.9% |
What to check before buying a 2020 SLC
The failure pattern for this year is specific enough to inspect against: tyres accounted for 5.3% of tests. Start there.
- Tyres (5.3% 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.
- Lighting & signalling (1.4% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Suspension (0.7% 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 SLCs pass their MOT?
93.0% of the 1,915 2020 Mercedes-Benz SLC MOT tests in this dataset passed — a 7.0% fail rate.
What is the most common MOT failure on a 2020 Mercedes-Benz SLC?
Tyres, recorded in 5.3% of tests, followed by lighting & signalling (1.4%).
Does the 2020 SLC get worse with mileage?
Its MOT fail rate rises from 6.0% in the 0-30k band to 11.8% in the 30-60k band.
Methodology & source. Based on 1,915 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.