Diesel Mazda 3: MOT pass rate

71% of diesel Mazda 3s pass the MOT first time, measured across 15,010 DVSA tests on that fuel type alone. Average mileage at test was 94,502.

Diesel against the other Mazda 3 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 Mazda 3 specifically, petrol is the strongest at 74.3%, and this diesel version sits 2.9 points below the 73.9% model average.

What it means if you are buying one

The diesel Mazda 3 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 Mazda 3 had covered 94,502 miles at test, against 73,153 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 Mazda 3 page separate age from fuel if you want to isolate one.

Most common MOT failures on a diesel Mazda 3

1. A spring or spring component fractured or seriously weakened, 4.7% of tests (2.08x the national rate for this defect)
2. A suspension pin, bush or joint excessively worn, 10.1% of tests (2.01x the national rate for this defect)
3. a brake lining or pad worn below 1.5mm, 4.1% of tests (1.93x the national rate for this defect)
4. A lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning, 3.3% of tests (1.49x the national rate for this defect)
5. Engine MIL illuminated indicating a malfunction, 1.9% of tests (1.48x the national rate for this defect)
6. A shock absorber damaged to the extent that it does not function or showing signs of severe leakage, 1.3% of tests (1.4x the national rate for this defect)
7. A tyre cords visible or damaged, 2.3% of tests (1.39x the national rate for this defect)
8. Brake pipe damaged or excessively corroded, 1.4% of tests (1.31x the national rate for this defect)
9. A rear registration plate lamp or light source missing or inoperative in the case of a single lamp or all lamps, 1.2% of tests (1.31x the national rate for this defect)
10. A tyre seriously damaged, 3.4% of tests (1.21x the national rate for this defect)

From 15,086 DVSA-tracked diesel Mazda 3 tests, 2024, split out from the Mazda 3's other fuel types. DVSA testers marked 5.81% 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 Mazda 3

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

1. A suspension component excessively damaged or corroded, 23% of tests (4.45x the national rate for this defect)
2. The strength or continuity of the load bearing structure within 30cm of any sub-frame, spring or suspension component mounting (a 'prescribed area') is significantly reduced or inadequately repaired, 3% of tests (2x the national rate for this defect)
3. Brake pipe damaged or excessively corroded, 11.9% of tests (1.92x the national rate for this defect), also fails
4. Vehicle structure corroded to the extent that the rigidity of the assembly is seriously reduced, 2.4% of tests (1.9x the national rate for this defect)
5. A suspension pin, bush or joint excessively worn, 23.3% of tests (1.75x the national rate for this defect), also fails
6. a brake lining or pad worn below 1.5mm, 14.3% of tests (1.53x the national rate for this defect), also fails
7. Brake disc or drum excessively weakened, insecure or fractured, 16.7% of tests (1.36x the national rate for this defect)
8. Tyre tread depth not in accordance with the requirements, 31.2% of tests (1.17x the national rate for this defect)
9. A tyre seriously damaged, 15.5% of tests, also fails
10. Fluid leaking excessively and likely to harm the environment or to pose a safety risk to other road users, 5.5% of tests

From 15,086 DVSA-tracked diesel Mazda 3 tests, 2024.

Other Mazda 3 fuel types

• Petrol Mazda 3 - 74.3%

All Mazda 3 MOT data · Every model