20,904 tests in 2025
Mercedes-Benz Cls reliability and MOT pass rate
77.4% passed first time. The 22.6% fail rate is 0.0 points better than the all-car average, on a median example 12 years old with 91,317 miles.
MOT pass rates / Mercedes-Benz
Pass rate
77.4%
22.6% of all cars failed; 22.6% of these did.
Fixed on the day
3%
Passed after a defect was put right during the visit.
Median at test
91,317 mi
12 years old.
Fail rate by age
| Age at test | Tests | Fail rate |
|---|---|---|
| 3-5 years | 536 | 19.4% |
| 6-9 years | 5,168 | 17.5% |
| 10-13 years | 8,082 | 23.4% |
| 14+ years | 7,118 | 25.7% |
What the Cls 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.
- Tyres2,223 dangerous40.9%
- Suspension75 dangerous38.6%
- Brakes456 dangerous26.8%
- Lamps, reflectors and electrical equipment3 dangerous14.9%
- Noise, emissions and leaks11 dangerous10.6%
- Road Wheels358 dangerous7.6%
- Visibility2 dangerous6%
- Steering18 dangerous5.2%
Is the Cls getting worse?
The fail rate rose 0.6 points to 22.7% from 2022 to 2025 while the median one tested aged 3 years. Ageing alone would predict about 7.4 points, so it is holding up better than the fleet average for its age.
| Year | Tests | Median age | Fail rate | All cars | |
|---|---|---|---|---|---|
| 2022 | 26,100 | 9 | 22.1% | 22.5% | |
| 2023 | 25,174 | 10 | 21.8% | 22.8% | |
| 2024 | 20,851 | 11 | 23.3% | 23.2% | |
| 2025 | 20,634 | 12 | 22.7% | 22.6% |
Fail rate is first attempts at class 4 tests. Median age is the age of a typical Cls 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 Cls in 2025, counted by how many tests each one appeared on.
- 1Coil spring: fractured or broken728 tests
- 2Condition: has ply or cords exposed645 tests
- 3Tread depth: tread depth below requirements of 1.6mm538 tests
- 4Ball joint: ball joint excessively worn426 tests
- 5Condition: has a cut in excess of the requirements deep enough to reach the ply or cords407 tests
- 6Rigid brake pipes: excessively corroded406 tests
- 7Malfunction indicator lamp: inoperative or indicates a malfunction318 tests
- 8Condition: fractured257 tests
What wears out first
Advisories are the tester flagging wear that is still legal. A typical Cls collects 2.79 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 1.6mm3,652 tests
- 2Rigid brake pipes: excessively corroded2,637 tests
- 3Brake discs: in such a condition that it is seriously weakened1,727 tests
- 4Brake pads: less than 1.5 mm thick1,590 tests
- 5Engine oil leaks: leaking excessively from engine1,374 tests
- 6Wheel bearings: has excessive play1,005 tests
- 7Ball joint: ball joint excessively worn876 tests
- 8Pins and bushes: pin or bush excessively worn874 tests
Questions
What is the Mercedes-Benz Cls MOT pass rate?
77.4% of the 20,904 Mercedes-Benz Cls first-attempt MOTs in 2025 passed. The fail rate of 22.6% compares with 22.6% across all cars. A further 3% passed after a defect was fixed during the test visit.
What does a Mercedes-Benz Cls usually fail on?
The single most common failure is "Coil spring: fractured or broken", recorded on 728 failed tests, followed by "Condition: has ply or cords exposed" and "Tread depth: tread depth below requirements of 1.6mm". By section, tyres appears in 40.9% of failures, suspension appears in 38.6% of failures, brakes appears in 26.8% of failures.
Does age change the odds?
Sharply. At 3 to 5 years old the fail rate was 19.4%; at 14+ years it was 25.7%. The median Mercedes-Benz Cls tested in 2025 was 12 years old with 91,317 miles.
Is the Mercedes-Benz Cls getting less reliable?
The fail rate rose 0.6 points to 22.7% from 2022 to 2025 while the median one tested aged 3 years. Ageing alone would predict about 7.4 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 Cls 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 38 safety recalls naming the Mercedes-Benz Cls: Mercedes-Benz Cls recalls.
Other Mercedes-Benz models
Checking a particular Cls?
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.