Mercedes-Benz GLS MOT pass rate & common failures
13,514 MOT tests on the Mercedes-Benz GLS (2010–2024) give it an 89.8% pass rate. Large SUVs of a similar age fail at 10.6%, so the GLS sits squarely on the average. Its most common failure areas are tyres, brakes and lighting & signalling.
What the MOT record shows
One area stands out: tyres, recorded in 6.9% of tests against 1.5% for the next-worst category.
At component level the recurring items are tread depth, brake pads and registration plates — tread depth alone was recorded 561 times.
Condition tracks the odometer closely. Failures run at 8.3% in the 0-30k band and 15.4% in the 150k+ band, a 7.1-point spread.
The petrol cars hold up better: 7.9% fail against 10.4% for diesel, a 2.6-point gap across 13,492 tests.
Tyres is the most common advisory, noted on 19.4% of tests — work that passed today but is likely due soon.
How it compares
Versions & engines
MOT records broken out by the engine designations buyers actually search for.
By model year
Every GLS model year with a usable sample. Years with their own detailed report are linked.
| Year | Tests | Pass rate | Fail rate | Most common failure |
|---|---|---|---|---|
| 2016 | 2,322 | 89.4% | 10.6% | Tyres |
| 2017 | 3,631 | 90.3% | 9.7% | Tyres |
| 2018 | 3,296 | 89.9% | 10.1% | Tyres |
| 2019 | 1,806 | 90.6% | 9.4% | Tyres |
| 2020 | 1,356 | 89.0% | 11.0% | Tyres |
| 2021 | 643 | 88.3% | 11.7% | Tyres |
| 2022 | 407 | 88.0% | 12.0% | Tyres |
| 2023 | 44 | 90.9% | 9.1% | Tyres |
Most common failures (all years)
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 6.9% | 936 |
| 2 | Brakes | 1.5% | 205 |
| 3 | Lighting & signalling | 1.1% | 156 |
| 4 | Other defects | 0.9% | 115 |
| 5 | Body, structure & corrosion | 0.8% | 102 |
| 6 | Visibility | 0.7% | 89 |
| 7 | Emissions & environmental | 0.6% | 78 |
| 8 | Suspension | 0.4% | 57 |
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 | 561 |
| 2 | Brake pads | 203 |
| 3 | Registration plates | 191 |
| 4 | Headlamp aim | 108 |
| 5 | Joints | 79 |
| 6 | Malfunction indicator lamp | 67 |
| 7 | Washers | 44 |
| 8 | Tyre pressure monitoring system | 43 |
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 | 19.4% | 2,618 |
| 2 | Brakes | 10.2% | 1,377 |
| 3 | Other defects | 6.2% | 836 |
| 4 | Visibility | 3.5% | 473 |
| 5 | Body, structure & corrosion | 2.4% | 324 |
| 6 | Suspension | 1.2% | 159 |
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 | 3,274 | 8.3% |
| 30-60k | 6,389 | 10.1% |
| 60-90k | 2,900 | 12.3% |
| 90-120k | 726 | 10.9% |
| 120-150k | 159 | 9.4% |
| 150k+ | 65 | 15.4% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Diesel | 12,185 | 10.4% |
| Petrol | 1,307 | 7.9% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 2,030 | 10.1% |
| 2022 | 2,417 | 9.6% |
| 2023 | 2,731 | 9.1% |
| 2024 | 3,015 | 10.7% |
| 2025 | 3,321 | 11.1% |
What to check before buying a Mercedes-Benz GLS
- 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.
- Brakes (1.5% 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.
- Lighting & signalling (1.1% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
Repair costs are rough UK ballpark ranges to set expectations, not quotes — actual prices vary widely by car, parts and garage.
Frequently asked questions
What is the MOT pass rate for the Mercedes-Benz GLS?
89.8% of the 13,514 Mercedes-Benz GLS MOT tests in this dataset passed, a 10.2% fail rate, across model years 2010–2024.
What does the Mercedes-Benz GLS most often fail its MOT on?
Tyres, recorded in 6.9% of tests, then brakes (1.5%).
How much does mileage affect GLS MOT results?
Fail rates run at 8.3% for cars in the 0-30k band and 15.4% for 150k+, a 7.1-point difference.
Is the petrol or diesel GLS more reliable at MOT time?
On MOT-testable defects the petrol fails 7.9% of the time against 10.4% for the diesel. This covers testable items only, not engine or gearbox reliability.
Methodology & source. Based on 13,514 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.