Mercedes-Benz Sl-Class MOT pass rate and common failures
In 2025, 82.9% of Mercedes-Benz Sl-Class MOT tests were a first-time pass, across 20,770 tests in Great Britain. For all cars it was 71.5%.
Compared with cars of the same age
Older cars fail more often, so a model that’s mostly a few years old will look better than one that’s mostly 12. These figures compare like with like.
At 3–5 years
90.7%
All cars: 86.1% (4.6 points better). 473 tests.
At 6–10 years
89.3%
All cars: 76.1% (13.2 points better). 3,300 tests.
At 11 years and over
81.5%
All cars: 61.3% (20.2 points better). 16,981 tests.
Pass rate by age
Figures by age, with typical mileage
| Age (years) | Tests | First-time pass | All cars | Typical mileage |
|---|---|---|---|---|
| 4 | 175 | 91.4% | 86.4% | 18,750 miles |
| 5 | 298 | 90.3% | 84.5% | 21,250 miles |
| 6 | 414 | 90.8% | 81.9% | 23,750 miles |
| 7 | 505 | 93.1% | 79.3% | 28,750 miles |
| 8 | 757 | 90.4% | 76.3% | 33,750 miles |
| 9 | 732 | 87.7% | 73.1% | 38,750 miles |
| 10 | 892 | 86.9% | 70.0% | 43,750 miles |
| 11 | 1,181 | 82.6% | 66.9% | 48,750 miles |
| 12 | 795 | 81.9% | 64.4% | 48,750 miles |
| 13 | 266 | 83.8% | 62.1% | 51,250 miles |
| 14 | 314 | 80.3% | 60.2% | 51,250 miles |
| 15 | 413 | 80.1% | 58.6% | 61,250 miles |
| 16 | 540 | 84.3% | 57.5% | 58,750 miles |
| 17 | 770 | 81.4% | 57.2% | 68,750 miles |
| 18 | 736 | 81.8% | 57.0% | 68,750 miles |
| 19 | 1,049 | 82.4% | 57.2% | 73,750 miles |
| 20+ | 10,917 | 81.1% | 61.4% | 81,250 miles |
Typical mileage is the median reading at the test, to the nearest 2,500 miles.
What fails most often
The share of Mercedes-Benz Sl-Class MOT tests that failed on at least one item in each area, against all cars. A test can fail on several areas at once.
| Area | Sl-Class | All cars |
|---|---|---|
| Lamps, reflectors and electrical equipment | 7.3% | 16.6% |
| Suspension | 7.0% | 13.7% |
| Tyres | 5.9% | 8.4% |
| Brakes | 5.2% | 10.2% |
| Visibility | 2.7% | 5.2% |
| Noise, emissions and leaks | 2.5% | 4.0% |
| Body, chassis, structure | 1.0% | 4.2% |
| Steering | 0.8% | 2.5% |
Most common reasons for failing
- Ball joint excessively worn failed 1.7% of tests · what this means
- Ball joint dust cover no longer prevents the ingress of dirt failed 1.5% of tests · what this means
- Condition: has a cut in excess of the requirements deep enough to reach the ply or cords failed 1.4% of tests
- Condition: has ply or cords exposed failed 1.3% of tests
- Coil spring: fractured or broken failed 1.3% of tests · what this means
- Condition: has a tear, caused by separation or partial failure of its structure failed 1.1% of tests
- Rigid brake pipes: excessively corroded failed 1.0% of tests · what this means
- Wipers: does not clear the windscreen effectively failed 1.0% of tests · what this means
- Headlamp aim: too low failed 0.9% of tests · what this means
- Tread depth below requirements of 1.6mm failed 0.8% of tests
Checking a particular Sl-Class?
See its own MOT history, mileage record and advisories in plain English. Free, no sign-up.
About these figures
- They cover every Sl-Class version DVSA records under this name (engines, trims and generations together), on its first MOT test of each visit. A “pass with rectification” (fixed within an hour) counts as a fail, as in DVSA’s own statistics.
- Cars under three years old are left out, because the few tested that young are mostly taxis.
- Fuel mix of the cars tested: petrol 99.9%, diesel 0.1%, liquefied petrolum gas (lpg) 0.0%.
- A pass rate describes the model, not any one car. How a car has been looked after matters more.
Download these figures (CSV) · Other Mercedes-Benz models · All makes
Source: DVSA anonymised MOT test data for 2025. Contains public sector information licensed under the Open Government Licence v3.0. Our own analysis; not produced or endorsed by DVSA.