Diesel BMW 4 Series: MOT pass rate

80.9% of diesel BMW 4 Series pass the MOT first time, measured across 655 DVSA tests on that fuel type alone. Average mileage at test was 98,673.

Diesel against the other BMW 4 Series 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 BMW 4 Series specifically, petrol is the strongest at 86.7%, and this diesel version sits 2.7 points below the 83.6% model average.

What it means if you are buying one

The diesel BMW 4 Series 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 BMW 4 Series had covered 98,673 miles at test, against 60,744 for the petrol. That is above average and into the range where cambelts and water pumps are due if they have not already been done, so ask for the service history rather than take the mileage on trust.

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 BMW 4 Series page separate age from fuel if you want to isolate one.

Most common MOT failures on a diesel BMW 4 Series

1. A shock absorber damaged to the extent that it does not function or showing signs of severe leakage, 3.2% of tests (3.41x the national rate for this defect)
2. A tyre cords visible or damaged, 4.9% of tests (2.94x the national rate for this defect)
3. Windscreen washers not working or not providing sufficient fluid to clear the windscreen, 2.5% of tests (1.46x the national rate for this defect)
4. Tyre tread depth not in accordance with the requirements, 3.9% of tests (1.21x the national rate for this defect)
5. A tyre seriously damaged, 3.4% of tests (1.21x the national rate for this defect)
6. A headlamp or light source missing, inoperative or more than ½ not functioning in the case of LED, 1.8% of tests (1.51x the national rate for this defect)
7. a brake lining or pad worn below 1.5mm, 1.7% of tests
8. A suspension pin, bush or joint excessively worn, 1.4% of tests
9. A tyre has a lump, bulge or tear caused by separation or partial failure of its structure. This includes any lifting of the tread rubber, 1.2% of tests (6.36x the national rate for this defect)
10. Parking brake efficiency below minimum requirement, 1.2% of tests

From 649 DVSA-tracked diesel BMW 4 Series tests, 2024, split out from the BMW 4 Series's other fuel types. DVSA testers marked 10.63% 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 BMW 4 Series

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

1. A shock absorber damaged to the extent that it does not function or showing signs of severe leakage, 8.5% of tests (2.17x the national rate for this defect), also fails
2. Brake disc or drum excessively weakened, insecure or fractured, 15.9% of tests (1.3x the national rate for this defect)
3. Brake disc or drum significantly and obviously worn, 4% of tests (1.26x the national rate for this defect)
4. a brake lining or pad worn below 1.5mm, 11.2% of tests (1.2x the national rate for this defect), also fails
5. Tyre tread depth not in accordance with the requirements, 31.7% of tests (1.19x the national rate for this defect), also fails
6. A tyre seriously damaged, 6.8% of tests, also fails
7. A suspension pin, bush or joint excessively worn, 5.1% of tests, also fails
8. Fluid leaking excessively and likely to harm the environment or to pose a safety risk to other road users, 2.6% of tests
9. A wheel badly distorted or wear between wheel and hub at spigot mounting, 1.5% of tests (1.44x the national rate for this defect)
10. Excessive fluctuation in brake effort through each wheel revolution., 1.1% of tests (1.27x the national rate for this defect)

From 649 DVSA-tracked diesel BMW 4 Series tests, 2024.

Other BMW 4 Series fuel types

• Petrol BMW 4 Series - 86.7%

All BMW 4 Series MOT data · Every model