Diesel Mercedes-Benz Cls: MOT pass rate

76.5% of diesel Mercedes-Benz Cls pass the MOT first time, measured across 20,881 DVSA tests on that fuel type alone. Average mileage at test was 93,151.

Diesel against the other Mercedes-Benz Cls versions

Why the fuel type changes the number

Diesels carry DPFs, EGR valves and stricter smoke limits, so emissions and exhaust faults account for failures petrol cars never see.

On the Mercedes-Benz Cls specifically, petrol is the strongest at 79.5%, and this diesel version sits 0.4 points below the 76.9% model average.

What it means if you are buying one

There is little to choose between fuel types on this model, so decide on running costs and mileage rather than MOT record. Buying a damaged one? run it through the analyzer, check the exact car, decode the VIN and check the mileage before you bid.

Mileage is part of the answer

The average diesel Mercedes-Benz Cls had covered 93,151 miles at test, against 85,773 for the petrol. That is above average, the point where suspension bushes, drop links and exhaust corrosion start showing up as advisories before they become failures.

Fuel type and mileage are tangled together: diesels are usually bought by higher-mileage drivers, so some of any gap between fuels is the miles rather than the engine. The per-year figures on the Mercedes-Benz Cls page separate age from fuel if you want to isolate one.

Most common MOT failures on a diesel Mercedes-Benz Cls

1. Any fracture or welding defect on a wheel, 1.4% of tests (24.37x the national rate for this defect)
2. Brake pipe damaged or excessively corroded, 4.1% of tests (3.81x the national rate for this defect)
3. A tyre cords visible or damaged, 4.2% of tests (2.5x the national rate for this defect)
4. A tyre seriously damaged, 5.4% of tests (1.92x the national rate for this defect)
5. A spring or spring component fractured or seriously weakened, 3.9% of tests (1.73x the national rate for this defect)
6. Tyre tread depth not in accordance with the requirements, 4.2% of tests (1.32x the national rate for this defect)
7. Engine MIL illuminated indicating a malfunction, 1.6% of tests (1.23x the national rate for this defect)
8. A direction indicator lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning, 0.8% of tests (1.19x the national rate for this defect)
9. A suspension pin, bush or joint excessively worn, 4.1% of tests
10. A suspension joint dust cover missing or no longer prevents the ingress of dirt etc, 2.1% of tests

From 21,057 DVSA-tracked diesel Mercedes-Benz Cls tests, 2024, split out from the Mercedes-Benz Cls's other fuel types. DVSA testers marked 8.3% of these flagged defects as "dangerous", against 5.11% nationally. See which fuel type fails on the most dangerous defects nationally for how that compares across the whole fleet.

Most common MOT advisories on a diesel Mercedes-Benz Cls

Flagged but doesn't fail the car, a different list from the failures above.

1. A wheel bearing with excessive play, 6.2% of tests (9.48x the national rate for this defect)
2. Brake pipe damaged or excessively corroded, 20.5% of tests (3.31x the national rate for this defect), also fails
3. A wheel badly distorted or wear between wheel and hub at spigot mounting, 2.3% of tests (2.15x the national rate for this defect)
4. Brake disc or drum significantly and obviously worn, 4.6% of tests (1.45x the national rate for this defect)
5. Tyre tread depth not in accordance with the requirements, 31.1% of tests (1.17x the national rate for this defect), also fails
6. A suspension pin, bush or joint excessively worn, 10.9% of tests, also fails
7. A tyre seriously damaged, 10.6% of tests, also fails
8. Brake disc or drum excessively weakened, insecure or fractured, 10.6% of tests
9. a brake lining or pad worn below 1.5mm, 9.8% of tests
10. Fluid leaking excessively and likely to harm the environment or to pose a safety risk to other road users, 5.8% of tests

From 21,057 DVSA-tracked diesel Mercedes-Benz Cls tests, 2024.

Other Mercedes-Benz Cls fuel types

• Petrol Mercedes-Benz Cls - 79.5%

All Mercedes-Benz Cls MOT data · Every model