2017 Mercedes-Benz GLS — MOT failures & pass rate
3,631 MOT tests on the 2017 Mercedes-Benz GLS are in this dataset, and 90.3% of them passed. That is 1.5 percentage points better than large SUVs of a similar age, which fail at 11.2%. Failures cluster in tyres, brakes and other defects.
What the MOT record shows
One area stands out: tyres, recorded in 6.6% of tests against 1.6% for the next-worst category.
At component level the recurring items are tread depth, registration plates and brake pads — tread depth alone was recorded 156 times.
Mileage matters less than usual here: the 2017 GLS fails 8.9% of the time in the 0-30k band and 10.3% at 120-150k, a spread of only 1.4 points.
Tyres is the most common advisory, noted on 20.0% of tests — work that passed today but is likely due soon.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 6.6% | 238 |
| 2 | Brakes | 1.6% | 59 |
| 3 | Other defects | 1.1% | 40 |
| 4 | Lighting & signalling | 1.0% | 35 |
| 5 | Visibility | 0.9% | 34 |
| 6 | Emissions & environmental | 0.6% | 23 |
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 | 156 |
| 2 | Registration plates | 65 |
| 3 | Brake pads | 50 |
| 4 | Washers | 24 |
| 5 | Malfunction indicator lamp | 22 |
| 6 | Joints | 20 |
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 | 20.0% | 727 |
| 2 | Brakes | 10.3% | 375 |
| 3 | Other defects | 5.9% | 213 |
| 4 | Body, structure & corrosion | 3.3% | 121 |
| 5 | Visibility | 3.1% | 114 |
| 6 | Emissions & environmental | 1.1% | 41 |
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 | 594 | 8.9% |
| 30-60k | 1,714 | 9.5% |
| 60-90k | 992 | 10.1% |
| 90-120k | 248 | 9.7% |
| 120-150k | 58 | 10.3% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Diesel | 3,183 | 10.0% |
| Petrol | 448 | 7.8% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 802 | 10.3% |
| 2022 | 768 | 10.4% |
| 2023 | 709 | 8.6% |
| 2024 | 690 | 9.3% |
| 2025 | 662 | 9.7% |
What to check before buying a 2017 GLS
The failure pattern for this year is specific enough to inspect against: tyres accounted for 6.6% of tests. Start there.
- Tyres (6.6% 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.
- Brakes (1.6% 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.
- Other defects (1.1% of tests): Miscellaneous items not in the main categories. Typical repair: varies.
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 2017 Mercedes-Benz GLSs pass their MOT?
90.3% of the 3,631 2017 Mercedes-Benz GLS MOT tests in this dataset passed — a 9.7% fail rate.
What is the most common MOT failure on a 2017 Mercedes-Benz GLS?
Tyres, recorded in 6.6% of tests, followed by brakes (1.6%).
Does the 2017 GLS get worse with mileage?
Its MOT fail rate rises from 8.9% in the 0-30k band to 10.3% in the 120-150k band.
Methodology & source. Based on 3,631 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.