2015 Mercedes-Benz Gl — MOT failures & pass rate
Across 3,579 MOT tests, the 2015 Mercedes-Benz Gl recorded an 88.5% pass rate. Against large SUVs of a similar age (13.7% fail rate), the 2015 Gl comes out 2.1pp better. Failures cluster in tyres, lighting & signalling and emissions & environmental.
What the MOT record shows
Tyres dominates the failure mix at 6.9% of all tests — 3.7 points clear of lighting & signalling, so it is the first thing to check.
At component level the recurring items are tread depth, headlamp aim and malfunction indicator lamp — tread depth alone was recorded 164 times.
Mileage is the strongest signal on the record: 8.2% of 0-30k cars fail, rising to 20.3% once past 150k — 2.5× the risk.
Advisories point at the next bill rather than this one: tyres was flagged on 21.4% of tests without failing them.
The trend is worsening — 9.5% of tests failed in 2021 against 11.9% in 2025, the usual pattern as a fleet ages.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 6.9% | 247 |
| 2 | Lighting & signalling | 3.2% | 115 |
| 3 | Emissions & environmental | 2.0% | 71 |
| 4 | Body, structure & corrosion | 1.3% | 46 |
| 5 | Brakes | 1.1% | 41 |
| 6 | Suspension | 1.0% | 36 |
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 | 164 |
| 2 | Headlamp aim | 67 |
| 3 | Malfunction indicator lamp | 66 |
| 4 | Joints | 43 |
| 5 | Stop lamp | 33 |
| 6 | Registration plates | 30 |
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 | 21.4% | 767 |
| 2 | Brakes | 12.7% | 456 |
| 3 | Other defects | 6.2% | 223 |
| 4 | Body, structure & corrosion | 4.5% | 163 |
| 5 | Visibility | 4.0% | 143 |
| 6 | Emissions & environmental | 3.3% | 117 |
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 | 170 | 8.2% |
| 30-60k | 1,161 | 10.2% |
| 60-90k | 1,377 | 11.7% |
| 90-120k | 635 | 12.8% |
| 120-150k | 172 | 15.1% |
| 150k+ | 64 | 20.3% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Diesel | 3,172 | 11.6% |
| Petrol | 407 | 11.1% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 718 | 9.5% |
| 2022 | 729 | 11.0% |
| 2023 | 721 | 12.8% |
| 2024 | 712 | 12.6% |
| 2025 | 699 | 11.9% |
What to check before buying a 2015 Gl
On a 2015 Gl, tyres is what the MOT record says goes wrong most — it appeared in 6.9% of tests. Check these areas before you commit.
- Tyres (6.9% 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.
- Lighting & signalling (3.2% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Emissions & environmental (2.0% 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 2015 Mercedes-Benz Gls pass their MOT?
88.5% of the 3,579 2015 Mercedes-Benz Gl MOT tests in this dataset passed — a 11.5% fail rate.
What is the most common MOT failure on a 2015 Mercedes-Benz Gl?
Tyres, recorded in 6.9% of tests, followed by lighting & signalling (3.2%).
Does the 2015 Gl get worse with mileage?
Its MOT fail rate rises from 8.2% in the 0-30k band to 20.3% in the 150k+ band.
Methodology & source. Based on 3,579 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.