2019 Mercedes-Benz SLC — MOT failures & pass rate
Across 4,300 MOT tests, the 2019 Mercedes-Benz SLC recorded a 93.2% pass rate. Against coupes & convertibles of a similar age (8.6% fail rate), the 2019 SLC comes out 1.8pp better. Failures cluster in tyres, lighting & signalling and emissions & environmental.
What the MOT record shows
One area stands out: tyres, recorded in 5.0% of tests against 1.2% for the next-worst category.
At component level the recurring items are headlamp aim, tread depth and registration plates — headlamp aim alone was recorded 52 times.
Mileage is the strongest signal on the record: 5.5% of 0-30k cars fail, rising to 18.9% once past 60-90k — 3.4× the risk.
Tyres is the most common advisory, noted on 21.2% of tests — work that passed today but is likely due soon.
The trend is worsening — 2.5% of tests failed in 2021 against 8.5% in 2025, the usual pattern as a fleet ages.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 5.0% | 214 |
| 2 | Lighting & signalling | 1.2% | 50 |
| 3 | Emissions & environmental | 0.6% | 24 |
| 4 | Brakes | 0.5% | 23 |
| 5 | Suspension | 0.4% | 17 |
| 6 | Other defects | 0.3% | 14 |
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 | 52 |
| 2 | Tread depth | 47 |
| 3 | Registration plates | 26 |
| 4 | Catalyst emissions | 15 |
| 5 | Headlamp | 14 |
| 6 | Tyre pressure monitoring system | 12 |
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 | 21.2% | 912 |
| 2 | Suspension | 3.4% | 148 |
| 3 | Other defects | 3.2% | 137 |
| 4 | Brakes | 2.3% | 98 |
| 5 | Road wheels | 1.6% | 69 |
| 6 | Visibility | 1.5% | 66 |
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 | 3,598 | 5.5% |
| 30-60k | 645 | 12.6% |
| 60-90k | 53 | 18.9% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 40 | 2.5% |
| 2022 | 1,098 | 5.3% |
| 2023 | 1,069 | 6.4% |
| 2024 | 1,023 | 7.1% |
| 2025 | 1,070 | 8.5% |
What to check before buying a 2019 SLC
The failure pattern for this year is specific enough to inspect against: tyres accounted for 5.0% of tests. Start there.
- Tyres (5.0% 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 (1.2% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Emissions & environmental (0.6% of tests): More common on older diesels (DPF/EGR) — can be expensive; check for warning lights and smoke. Typical repair: £100–£600.
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 2019 Mercedes-Benz SLCs pass their MOT?
93.2% of the 4,300 2019 Mercedes-Benz SLC MOT tests in this dataset passed — a 6.8% fail rate.
What is the most common MOT failure on a 2019 Mercedes-Benz SLC?
Tyres, recorded in 5.0% of tests, followed by lighting & signalling (1.2%).
Does the 2019 SLC get worse with mileage?
Its MOT fail rate rises from 5.5% in the 0-30k band to 18.9% in the 60-90k band.
Methodology & source. Based on 4,300 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.