2005 Mercedes-Benz S-Class — MOT failures & pass rate
Across 3,646 MOT tests, the 2005 Mercedes-Benz S-Class recorded an 80.0% pass rate. That is 4.1 percentage points better than executive cars of a similar age, which fail at 24.1%. Failures cluster in lighting & signalling, suspension and brakes.
What the MOT record shows
Lighting & signalling dominates the failure mix at 11.2% of all tests — 3.0 points clear of suspension, so it is the first thing to check.
At component level the recurring items are ball joint, tread depth and headlamp aim — ball joint alone was recorded 182 times.
Mileage is the strongest signal on the record: 6.4% of 0-30k cars fail, rising to 23.6% once past 150k — 3.7× the risk.
Split by fuel, diesel examples fail 2.7pp more often than petrol ones (20.7% vs 18.1%) — worth weighing if you have a choice.
Advisories point at the next bill rather than this one: brakes was flagged on 35.6% of tests without failing them.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 11.2% | 409 |
| 2 | Suspension | 8.2% | 299 |
| 3 | Brakes | 6.9% | 250 |
| 4 | Tyres | 5.4% | 196 |
| 5 | Visibility | 3.4% | 122 |
| 6 | Steering | 2.3% | 83 |
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 | 182 |
| 2 | Tread depth | 156 |
| 3 | Headlamp aim | 142 |
| 4 | Rigid brake pipes | 141 |
| 5 | Headlamp | 121 |
| 6 | Pins and bushes | 107 |
Top advisory categories
Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.
| # | Category | % of tests with advisory | Tests |
|---|---|---|---|
| 1 | Brakes | 35.6% | 1,297 |
| 2 | Tyres | 26.4% | 962 |
| 3 | Suspension | 23.2% | 845 |
| 4 | Lighting & signalling | 12.5% | 457 |
| 5 | Other defects | 10.8% | 392 |
| 6 | Emissions & environmental | 9.8% | 356 |
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 | 47 | 6.4% |
| 30-60k | 259 | 13.9% |
| 60-90k | 565 | 14.0% |
| 90-120k | 895 | 19.3% |
| 120-150k | 872 | 22.5% |
| 150k+ | 972 | 23.6% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Diesel | 2,594 | 20.7% |
| Petrol | 1,052 | 18.1% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 965 | 20.2% |
| 2022 | 846 | 20.2% |
| 2023 | 725 | 17.7% |
| 2024 | 619 | 21.6% |
| 2025 | 491 | 20.4% |
What to check before buying a 2005 S-Class
On a 2005 S-Class, lighting & signalling is what the MOT record says goes wrong most — it appeared in 11.2% of tests. Check these areas before you commit.
- Lighting & signalling (11.2% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Suspension (8.2% 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.
- Brakes (6.9% of tests): Pads/discs are routine wear; binding, imbalance or corroded pipes are more serious — test for pulling under braking. Typical repair: £100–£350 per axle.
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 2005 Mercedes-Benz S-Classs pass their MOT?
80.0% of the 3,646 2005 Mercedes-Benz S-Class MOT tests in this dataset passed — a 20.0% fail rate.
What is the most common MOT failure on a 2005 Mercedes-Benz S-Class?
Lighting & signalling, recorded in 11.2% of tests, followed by suspension (8.2%).
Does the 2005 S-Class get worse with mileage?
Its MOT fail rate rises from 6.4% in the 0-30k band to 23.6% in the 150k+ band.
Methodology & source. Based on 3,646 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.