Mercedes-Benz E400d — MOT pass rate & failures
The Mercedes-Benz E400d passed 85.5% of its 2,194 MOT tests, covering model years 2018–2023. That is 1.9 percentage points better than the 16.4% fail rate across all Mercedes-Benz E-Class versions, so the E400d is a stronger pick within the range. Failures concentrate in tyres, road wheels and suspension.
What the MOT record shows
At component level the recurring items are ball joint, headlamp aim and registration plates — ball joint alone was recorded 33 times.
Mileage matters less than usual here: the E400d fails 13.5% of the time in the 0-30k band and 10.5% at 90-120k, a spread of only 3.0 points.
Advisories point at the next bill rather than this one: tyres was flagged on 12.5% of tests without failing them.
The trend is worsening — 10.0% of tests failed in 2022 against 13.6% in 2025, the usual pattern as a fleet ages.
How it compares
By model year
| Year | Tests | Pass rate | Fail rate |
|---|---|---|---|
| 2019 | 540 | 87.8% | 12.2% |
| 2020 | 943 | 85.4% | 14.6% |
| 2021 | 516 | 82.0% | 18.0% |
| 2022 | 168 | 87.5% | 12.5% |
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 9.4% | 206 |
| 2 | Road wheels | 5.3% | 116 |
| 3 | Suspension | 1.4% | 31 |
| 4 | Lighting & signalling | 1.1% | 25 |
| 5 | Other defects | 0.5% | 12 |
| 6 | Brakes | 0.5% | 10 |
| 7 | Emissions & environmental | 0.4% | 9 |
| 8 | Visibility | 0.3% | 7 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Ball joint | 33 |
| 2 | Headlamp aim | 29 |
| 3 | Registration plates | 18 |
| 4 | Tread depth | 16 |
| 5 | Malfunction indicator lamp | 9 |
| 6 | Brake pads | 8 |
Top advisory categories
Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.
| # | Category | % of tests with advisory | Tests |
|---|---|---|---|
| 1 | Tyres | 12.5% | 275 |
| 2 | Brakes | 7.6% | 167 |
| 3 | Suspension | 4.9% | 107 |
| 4 | Other defects | 2.8% | 62 |
| 5 | Visibility | 2.2% | 49 |
| 6 | Road wheels | 0.6% | 14 |
Failure rate by mileage
Higher-mileage cars tend to fail more — often the most useful guide to real condition.
| Mileage band | Tests | Fail rate |
|---|---|---|
| 0-30k | 939 | 13.5% |
| 30-60k | 1,013 | 15.5% |
| 60-90k | 193 | 15.0% |
| 90-120k | 38 | 10.5% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2022 | 170 | 10.0% |
| 2023 | 467 | 14.6% |
| 2024 | 702 | 16.8% |
| 2025 | 852 | 13.6% |
What to check before buying a Mercedes-Benz E400d
Focus on the areas it most often fails on — and remember MOT data covers testable defects only, not engine or gearbox health.
- Tyres (9.4% of tests): Usually a quick, known-cost fix, but check tread, age and uneven wear (which can hint at alignment or suspension issues). Typical repair: £50–£120 per tyre.
- Road wheels (5.3% of tests): Damaged or corroded wheels, missing/loose fixings — generally a moderate fix. Typical repair: £80–£250.
- Suspension (1.4% of tests): Worn drop links, bushes, springs or shocks — listen for knocks over bumps and check for uneven tyre wear. Typical repair: £150–£450 per corner.
Repair costs are rough UK ballpark ranges to set expectations, not quotes — actual prices vary widely by car, parts and garage.
Frequently asked questions
How reliable is the Mercedes-Benz E400d at MOT time?
85.5% of the 2,194 Mercedes-Benz E400d MOT tests in this dataset passed — a 14.5% fail rate, better than the 16.4% average across all E-Class versions.
What is the most common MOT failure on a Mercedes-Benz E400d?
Tyres, recorded in 9.4% of tests, followed by road wheels (5.3%).
Does the E400d get worse with mileage?
Its MOT fail rate rises from 13.5% in the 0-30k band to 10.5% in the 90-120k band.
Methodology & source. Based on 2,194 MOT tests. Dataset: DVSA MOT testing data (2021,2022,2023,2024,2025). Data last updated 2026-07-27. Figures reflect MOT-testable defects only — read the methodology for how these are calculated and what they don't measure.