1999 Mercedes-Benz Ml — MOT failures & pass rate
The 1999 Mercedes-Benz Ml passed 72.5% of its 1,771 recorded MOT tests. Against large SUVs of a similar age (24.7% fail rate), the 1999 Ml comes out 2.8pp worse. Failures cluster in lighting & signalling, brakes and suspension.
What the MOT record shows
Lighting & signalling dominates the failure mix at 19.3% of all tests — 6.6 points clear of brakes, so it is the first thing to check.
At component level the recurring items are headlamp aim, headlamp and coil spring — headlamp aim alone was recorded 183 times.
Condition tracks the odometer closely. Failures run at 18.2% in the 30-60k band and 30.7% in the 150k+ band, a 12.5-point spread.
Advisories point at the next bill rather than this one: brakes was flagged on 42.9% of tests without failing them.
The trend is improving — the fail rate fell from 28.6% in 2021 to 24.4% in 2025, as the worst-kept examples leave the fleet.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 19.3% | 341 |
| 2 | Brakes | 12.7% | 225 |
| 3 | Suspension | 11.4% | 202 |
| 4 | Visibility | 6.6% | 117 |
| 5 | Body, structure & corrosion | 6.0% | 107 |
| 6 | Emissions & environmental | 5.2% | 92 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Headlamp aim | 183 |
| 2 | Headlamp | 110 |
| 3 | Coil spring | 88 |
| 4 | Rigid brake pipes | 85 |
| 5 | Track rod end | 85 |
| 6 | Catalyst emissions | 84 |
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 | 42.9% | 759 |
| 2 | Emissions & environmental | 39.8% | 705 |
| 3 | Suspension | 38.4% | 680 |
| 4 | Lighting & signalling | 26.2% | 464 |
| 5 | Tyres | 24.4% | 433 |
| 6 | Other defects | 17.8% | 316 |
Failure rate by mileage
Higher-mileage cars tend to fail more — often the most useful guide to real condition.
| Mileage band | Tests | Fail rate |
|---|---|---|
| 30-60k | 55 | 18.2% |
| 60-90k | 188 | 19.7% |
| 90-120k | 424 | 27.4% |
| 120-150k | 540 | 27.8% |
| 150k+ | 554 | 30.7% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 583 | 28.6% |
| 2022 | 426 | 27.7% |
| 2023 | 315 | 27.3% |
| 2024 | 246 | 27.2% |
| 2025 | 201 | 24.4% |
What to check before buying a 1999 Ml
On a 1999 Ml, lighting & signalling is what the MOT record says goes wrong most — it appeared in 19.3% of tests. Check these areas before you commit.
- Lighting & signalling (19.3% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Brakes (12.7% 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.
- Suspension (11.4% 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 many 1999 Mercedes-Benz Mls pass their MOT?
72.5% of the 1,771 1999 Mercedes-Benz Ml MOT tests in this dataset passed — a 27.5% fail rate.
What is the most common MOT failure on a 1999 Mercedes-Benz Ml?
Lighting & signalling, recorded in 19.3% of tests, followed by brakes (12.7%).
Does the 1999 Ml get worse with mileage?
Its MOT fail rate rises from 18.2% in the 30-60k band to 30.7% in the 150k+ band.
Methodology & source. Based on 1,771 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.