2014 Mercedes-Benz S-Class — MOT failures & pass rate
Across 9,292 MOT tests, the 2014 Mercedes-Benz S-Class recorded a 90.1% pass rate. Executive cars of a similar age fail 15.4% of the time, so this is 5.5pp better than the group it competes with. Failures cluster in tyres, suspension and emissions & environmental.
What the MOT record shows
No single area dominates — tyres (4.9%) and suspension (2.5%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are tread depth, ball joint and malfunction indicator lamp — tread depth alone was recorded 255 times.
Mileage matters less than usual here: the 2014 S-Class fails 6.9% of the time in the 0-30k band and 10.0% at 150k+, a spread of only 3.1 points.
Fuel type barely separates them — hybrid fails 8.8% of the time against 10.2% for diesel.
Advisories point at the next bill rather than this one: tyres was flagged on 18.2% of tests without failing them.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 4.9% | 458 |
| 2 | Suspension | 2.5% | 233 |
| 3 | Emissions & environmental | 1.7% | 154 |
| 4 | Visibility | 1.6% | 148 |
| 5 | Lighting & signalling | 1.4% | 130 |
| 6 | Brakes | 1.2% | 112 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Tread depth | 255 |
| 2 | Ball joint | 215 |
| 3 | Malfunction indicator lamp | 138 |
| 4 | Washers | 118 |
| 5 | Registration plates | 78 |
| 6 | Brake pads | 78 |
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 | 18.2% | 1,693 |
| 2 | Brakes | 13.1% | 1,221 |
| 3 | Suspension | 7.0% | 647 |
| 4 | Other defects | 3.2% | 299 |
| 5 | Visibility | 3.0% | 280 |
| 6 | Emissions & environmental | 1.7% | 162 |
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 | 628 | 6.9% |
| 30-60k | 2,338 | 8.6% |
| 60-90k | 2,617 | 11.2% |
| 90-120k | 1,617 | 9.7% |
| 120-150k | 976 | 11.6% |
| 150k+ | 1,115 | 10.0% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Diesel | 6,841 | 10.2% |
| Petrol | 1,600 | 9.1% |
| Hybrid | 741 | 8.8% |
| Electric | 83 | 8.4% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 1,994 | 9.8% |
| 2022 | 1,933 | 9.9% |
| 2023 | 1,891 | 10.5% |
| 2024 | 1,760 | 9.4% |
| 2025 | 1,714 | 9.7% |
What to check before buying a 2014 S-Class
On a 2014 S-Class, tyres is what the MOT record says goes wrong most — it appeared in 4.9% of tests. Check these areas before you commit.
- Tyres (4.9% 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.
- Suspension (2.5% 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.
- Emissions & environmental (1.7% of tests): More common on older diesels (DPF/EGR) — can be expensive; check for warning lights and smoke. Typical repair: £100–£600.
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 many 2014 Mercedes-Benz S-Classs pass their MOT?
90.1% of the 9,292 2014 Mercedes-Benz S-Class MOT tests in this dataset passed — a 9.9% fail rate.
What is the most common MOT failure on a 2014 Mercedes-Benz S-Class?
Tyres, recorded in 4.9% of tests, followed by suspension (2.5%).
Does the 2014 S-Class get worse with mileage?
Its MOT fail rate rises from 6.9% in the 0-30k band to 10.0% in the 150k+ band.
Methodology & source. Based on 9,292 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.