2009 Mercedes-Benz Gl — MOT failures & pass rate
630 MOT tests on the 2009 Mercedes-Benz Gl are in this dataset, and 82.5% of them passed. That is 4.2 percentage points better than large SUVs of a similar age, which fail at 21.6%. Failures cluster in lighting & signalling, brakes and suspension.
What the MOT record shows
One area stands out: lighting & signalling, recorded in 13.0% of tests against 6.5% for the next-worst category.
At component level the recurring items are side repeaters, position lamp and rigid brake pipes — side repeaters alone was recorded 32 times.
Mileage matters less than usual here: the 2009 Gl fails 16.3% of the time in the 60-90k band and 16.5% at 150k+, a spread of only 0.2 points.
Brakes is the most common advisory, noted on 27.5% of tests — work that passed today but is likely due soon.
The trend is improving — the fail rate fell from 17.2% in 2021 to 11.5% in 2025, as the worst-kept examples leave the fleet.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 13.0% | 82 |
| 2 | Brakes | 6.5% | 41 |
| 3 | Suspension | 4.4% | 28 |
| 4 | Tyres | 3.5% | 22 |
| 5 | Emissions & environmental | 3.0% | 19 |
| 6 | Visibility | 2.4% | 15 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Side repeaters | 32 |
| 2 | Position lamp | 27 |
| 3 | Rigid brake pipes | 22 |
| 4 | Headlamp | 18 |
| 5 | Headlamp aim | 16 |
| 6 | Shock absorbers | 14 |
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 | 27.5% | 173 |
| 2 | Tyres | 25.1% | 158 |
| 3 | Emissions & environmental | 19.5% | 123 |
| 4 | Suspension | 16.0% | 101 |
| 5 | Lighting & signalling | 9.5% | 60 |
| 6 | Other defects | 9.4% | 59 |
Failure rate by mileage
Higher-mileage cars tend to fail more — often the most useful guide to real condition.
| Mileage band | Tests | Fail rate |
|---|---|---|
| 60-90k | 86 | 16.3% |
| 90-120k | 244 | 15.6% |
| 120-150k | 170 | 21.2% |
| 150k+ | 109 | 16.5% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Diesel | 597 | 17.9% |
| Petrol | 33 | 9.1% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 145 | 17.2% |
| 2022 | 134 | 18.7% |
| 2023 | 136 | 19.1% |
| 2024 | 119 | 19.3% |
| 2025 | 96 | 11.5% |
What to check before buying a 2009 Gl
The failure pattern for this year is specific enough to inspect against: lighting & signalling accounted for 13.0% of tests. Start there.
- Lighting & signalling (13.0% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Brakes (6.5% 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 (4.4% 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 2009 Mercedes-Benz Gls pass their MOT?
82.5% of the 630 2009 Mercedes-Benz Gl MOT tests in this dataset passed — a 17.5% fail rate.
What is the most common MOT failure on a 2009 Mercedes-Benz Gl?
Lighting & signalling, recorded in 13.0% of tests, followed by brakes (6.5%).
Does the 2009 Gl get worse with mileage?
Its MOT fail rate rises from 16.3% in the 60-90k band to 16.5% in the 150k+ band.
Methodology & source. Based on 630 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.