2019 Mercedes-Benz Sl — MOT failures & pass rate
1,488 MOT tests on the 2019 Mercedes-Benz Sl are in this dataset, and 93.9% of them passed. Against coupes & convertibles of a similar age (8.5% fail rate), the 2019 Sl comes out 2.4pp better. Failures cluster in tyres, lighting & signalling and suspension.
What the MOT record shows
Tyres dominates the failure mix at 5.2% of all tests — 4.1 points clear of lighting & signalling, so it is the first thing to check.
At component level the recurring items are headlamp aim, tread depth and washers — headlamp aim alone was recorded 17 times.
Advisories point at the next bill rather than this one: tyres was flagged on 13.4% of tests without failing them.
The trend is improving — the fail rate fell from 12.0% in 2021 to 6.5% in 2025, as the worst-kept examples leave the fleet.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 5.2% | 77 |
| 2 | Lighting & signalling | 1.1% | 16 |
| 3 | Suspension | 0.5% | 8 |
| 4 | Visibility | 0.5% | 7 |
| 5 | Emissions & environmental | 0.3% | 5 |
| 6 | Body, structure & corrosion | 0.2% | 3 |
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 | 17 |
| 2 | Tread depth | 9 |
| 3 | Washers | 7 |
| 4 | Catalyst emissions | 6 |
| 5 | Ball joint | 5 |
| 6 | Tyre pressure monitoring system | 3 |
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 | 13.4% | 199 |
| 2 | Visibility | 1.8% | 26 |
| 3 | Other defects | 1.6% | 24 |
| 4 | Brakes | 1.4% | 21 |
| 5 | Road wheels | 1.2% | 18 |
| 6 | Suspension | 1.1% | 17 |
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 | 1,269 | 5.5% |
| 30-60k | 194 | 8.8% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 50 | 12.0% |
| 2022 | 355 | 4.5% |
| 2023 | 378 | 6.9% |
| 2024 | 350 | 5.7% |
| 2025 | 355 | 6.5% |
What to check before buying a 2019 Sl
On a 2019 Sl, tyres is what the MOT record says goes wrong most — it appeared in 5.2% of tests. Check these areas before you commit.
- Tyres (5.2% 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 (1.1% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Suspension (0.5% 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 2019 Mercedes-Benz Sls pass their MOT?
93.9% of the 1,488 2019 Mercedes-Benz Sl MOT tests in this dataset passed — a 6.1% fail rate.
What is the most common MOT failure on a 2019 Mercedes-Benz Sl?
Tyres, recorded in 5.2% of tests, followed by lighting & signalling (1.1%).
Does the 2019 Sl get worse with mileage?
Its MOT fail rate rises from 5.5% in the 0-30k band to 8.8% in the 30-60k band.
Methodology & source. Based on 1,488 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.