24,603 tests in 2025
Mercedes-Benz S-Class reliability and MOT pass rate
86.6% passed first time. The 13.4% fail rate is 9.2 points better than the all-car average, on a median example 10 years old with 85,328 miles.
MOT pass rates / Mercedes-Benz
Pass rate
86.6%
22.6% of all cars failed; 13.4% of these did.
Fixed on the day
2.8%
Passed after a defect was put right during the visit.
Median at test
85,328 mi
10 years old.
Fail rate by age
| Age at test | Tests | Fail rate |
|---|---|---|
| 3-5 years | 1,890 | 7.7% |
| 6-9 years | 8,713 | 10% |
| 10-13 years | 5,430 | 12.3% |
| 14+ years | 7,965 | 19.9% |
What the S-Class fails on
Share of failed tests with at least one fail item in each DVSA inspection section. A test can fail in several sections at once.
- Suspension67 dangerous35.1%
- Tyres1,227 dangerous34.3%
- Brakes438 dangerous27.5%
- Lamps, reflectors and electrical equipment9 dangerous16.3%
- Noise, emissions and leaks9 dangerous15.8%
- Visibility2 dangerous12%
- Body, chassis, structure16 dangerous5.8%
- Seat belts and supplementary restraint systems1 dangerous5.3%
Is the S-Class getting worse?
The fail rate fell 0.9 points to 14.1% from 2022 to 2025 while the median one tested aged 3 years. Ageing alone would predict about 8 points, so it is holding up better than the fleet average for its age.
| Year | Tests | Median age | Fail rate | All cars | |
|---|---|---|---|---|---|
| 2022 | 29,755 | 8 | 15% | 22.5% | |
| 2023 | 27,851 | 9 | 14.5% | 22.8% | |
| 2024 | 22,667 | 10 | 15% | 23.2% | |
| 2025 | 22,182 | 11 | 14.1% | 22.6% |
Fail rate is first attempts at class 4 tests. Median age is the age of a typical S-Class at its test that year, and it is the number to watch: across the whole fleet each extra year of age adds roughly 1.9 points to the fail rate, so a model whose age and fail rate rise together is simply getting older.
The exact defects that fail it
Every failure item DVSA recorded against a S-Class in 2025, counted by how many tests each one appeared on.
- 1Ball joint: ball joint excessively worn685 tests
- 2Tread depth: tread depth below requirements of 1.6mm391 tests
- 3Condition: has ply or cords exposed294 tests
- 4Malfunction indicator lamp: inoperative or indicates a malfunction288 tests
- 5Condition: has a cut in excess of the requirements deep enough to reach the ply or cords252 tests
- 6Rbt (sp): efficiency below requirements197 tests
- 7Pins and bushes: pin or bush excessively worn194 tests
- 8Ball joint dust cover: ball joint dust cover no longer prevents the ingress of dirt191 tests
What wears out first
Advisories are the tester flagging wear that is still legal. A typical S-Class collects 2.59 of them per test, and these are the ones that come up most. Treat it as the running-repairs list for the next year or two.
- 1Tread depth: tread depth below requirements of 1.6mm3,342 tests
- 2Brake discs: in such a condition that it is seriously weakened1,745 tests
- 3Ball joint: ball joint excessively worn1,488 tests
- 4Brake pads: less than 1.5 mm thick1,454 tests
- 5Rigid brake pipes: excessively corroded1,449 tests
- 6Engine oil leaks: leaking excessively from engine1,352 tests
- 7Brake discs: significantly and obviously worn753 tests
- 8Condition: has a tear, caused by separation or partial failure of its structure750 tests
Questions
What is the Mercedes-Benz S-Class MOT pass rate?
86.6% of the 24,603 Mercedes-Benz S-Class first-attempt MOTs in 2025 passed. The fail rate of 13.4% compares with 22.6% across all cars. A further 2.8% passed after a defect was fixed during the test visit.
What does a Mercedes-Benz S-Class usually fail on?
The single most common failure is "Ball joint: ball joint excessively worn", recorded on 685 failed tests, followed by "Tread depth: tread depth below requirements of 1.6mm" and "Condition: has ply or cords exposed". By section, suspension appears in 35.1% of failures, tyres appears in 34.3% of failures, brakes appears in 27.5% of failures.
Does age change the odds?
Sharply. At 3 to 5 years old the fail rate was 7.7%; at 14+ years it was 19.9%. The median Mercedes-Benz S-Class tested in 2025 was 10 years old with 85,328 miles.
Is the Mercedes-Benz S-Class getting less reliable?
The fail rate fell 0.9 points to 14.1% from 2022 to 2025 while the median one tested aged 3 years. Ageing alone would predict about 8 points, so it is holding up better than the fleet average for its age.
First-attempt class 4 tests, 2025, from DVSA’s anonymised MOT data (OGL v3, retrieved 2026-09-12). DVSA records newer cars trim by trim; this page adds every S-Class trim together. Year-on-year figures come from the same DVSA extracts for 2026 and earlier years. Full method on the pass rates hub.
DVSA has published 87 safety recalls naming the Mercedes-Benz S-Class: Mercedes-Benz S-Class recalls.
Other Mercedes-Benz models
Checking a particular S-Class?
The odds above are the model. The car in front of you has its own record: every test, every advisory, the mileage at each one.
Due a test? Find an approved MOT station near you.