Diesel Mercedes-Benz Cla: MOT pass rate

80.4% of diesel Mercedes-Benz Clas pass the MOT first time, measured across 23,165 DVSA tests on that fuel type alone. Average mileage at test was 77,920.

Diesel against the other Mercedes-Benz Cla 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 Cla specifically, petrol is the strongest at 85.2%, and this diesel version sits 2.9 points below the 83.3% model average.

What it means if you are buying one

The diesel Mercedes-Benz Cla fails more often than the model average, so budget for the items that catch this fuel type and treat a fresh MOT as worth paying for. 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 Cla had covered 77,920 miles at test, against 47,475 for the petrol. That is a shade above the middle of the range, still ordinary wear rather than a red flag, but worth checking against the service book for the car's age.

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 Cla page separate age from fuel if you want to isolate one.

Most common MOT failures on a diesel Mercedes-Benz Cla

1. Any fracture or welding defect on a wheel, 0.8% of tests (13.95x the national rate for this defect)
2. An SRS malfunction indicator lamp (MIL) indicates a system malfunction, 1.1% of tests (2.61x the national rate for this defect)
3. A tyre cords visible or damaged, 3.3% of tests (1.95x the national rate for this defect)
4. Engine MIL illuminated indicating a malfunction, 2.5% of tests (1.94x the national rate for this defect)
5. A tyre seriously damaged, 4.7% of tests (1.69x the national rate for this defect)
6. A spring or spring component fractured or seriously weakened, 3.3% of tests (1.45x the national rate for this defect)
7. A suspension joint dust cover missing or no longer prevents the ingress of dirt etc, 2.7% of tests (1.45x the national rate for this defect)
8. Brake disc or drum significantly and obviously worn, 1% of tests (1.27x the national rate for this defect)
9. Tyre tread depth not in accordance with the requirements, 3.6% of tests
10. a brake lining or pad worn below 1.5mm, 2.1% of tests

From 23,268 DVSA-tracked diesel Mercedes-Benz Cla tests, 2024, split out from the Mercedes-Benz Cla's other fuel types. DVSA testers marked 9.84% 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 Cla

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

1. A wheel badly distorted or wear between wheel and hub at spigot mounting, 2.2% of tests (2.03x the national rate for this defect)
2. Brake disc or drum significantly and obviously worn, 5.7% of tests (1.78x the national rate for this defect), also fails
3. Excessive fluctuation in brake effort through each wheel revolution., 1.1% of tests (1.31x the national rate for this defect)
4. Brake disc or drum excessively weakened, insecure or fractured, 14.4% of tests (1.18x the national rate for this defect)
5. Tyre tread depth not in accordance with the requirements, 30.6% of tests, also fails
6. A tyre seriously damaged, 13.5% of tests, also fails
7. a brake lining or pad worn below 1.5mm, 10.4% of tests, also fails
8. A suspension pin, bush or joint excessively worn, 2.7% of tests
9. A spring or spring component fractured or seriously weakened, 1.4% of tests, also fails
10. Brake pipe damaged or excessively corroded, 1.3% of tests

From 23,268 DVSA-tracked diesel Mercedes-Benz Cla tests, 2024.

Other Mercedes-Benz Cla fuel types

• Petrol Mercedes-Benz Cla - 85.2%

All Mercedes-Benz Cla MOT data · Every model