2020 Mercedes-Benz GLA — MOT failures & pass rate
Across 29,696 MOT tests, the 2020 Mercedes-Benz GLA recorded a 93.1% pass rate. Against small SUVs of a similar age (7.9% fail rate), the 2020 GLA comes out 1.0pp better. Failures cluster in tyres, visibility and brakes.
What the MOT record shows
No single area dominates — tyres (3.6%) and visibility (1.7%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are brake pads, tread depth and wipers — brake pads alone was recorded 545 times.
Mileage matters less than usual here: the 2020 GLA fails 5.1% of the time in the 0-30k band and 6.9% at 90-120k, a spread of only 1.8 points.
Fuel type barely separates them — diesel fails 6.2% of the time against 7.1% for hybrid.
Tyres is the most common advisory, noted on 20.1% of tests — work that passed today but is likely due soon.
The trend is worsening — 4.9% of tests failed in 2022 against 7.9% in 2025, the usual pattern as a fleet ages.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 3.6% | 1,075 |
| 2 | Visibility | 1.7% | 511 |
| 3 | Brakes | 1.7% | 506 |
| 4 | Lighting & signalling | 1.1% | 334 |
| 5 | Suspension | 0.5% | 152 |
| 6 | Emissions & environmental | 0.3% | 96 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Brake pads | 545 |
| 2 | Tread depth | 457 |
| 3 | Wipers | 344 |
| 4 | Headlamp aim | 336 |
| 5 | Washers | 206 |
| 6 | Registration plates | 96 |
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 | 20.1% | 5,954 |
| 2 | Brakes | 10.4% | 3,083 |
| 3 | Other defects | 6.3% | 1,870 |
| 4 | Visibility | 2.5% | 740 |
| 5 | Suspension | 1.0% | 292 |
| 6 | Lighting & signalling | 0.3% | 82 |
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 | 17,680 | 5.1% |
| 30-60k | 10,849 | 9.4% |
| 60-90k | 1,054 | 11.3% |
| 90-120k | 87 | 6.9% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Petrol | 25,711 | 7.0% |
| Diesel | 2,812 | 6.2% |
| Hybrid | 1,173 | 7.1% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2022 | 556 | 4.9% |
| 2023 | 9,886 | 6.1% |
| 2024 | 9,608 | 6.8% |
| 2025 | 9,638 | 7.9% |
What to check before buying a 2020 GLA
The failure pattern for this year is specific enough to inspect against: tyres accounted for 3.6% of tests. Start there.
- Tyres (3.6% 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.
- Visibility (1.7% of tests): Wipers, washers, mirrors and screen damage — usually inexpensive, but check for chips in the driver's line of sight. Typical repair: £15–£150.
- Brakes (1.7% 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.
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 2020 Mercedes-Benz GLAs pass their MOT?
93.1% of the 29,696 2020 Mercedes-Benz GLA MOT tests in this dataset passed — a 6.9% fail rate.
What is the most common MOT failure on a 2020 Mercedes-Benz GLA?
Tyres, recorded in 3.6% of tests, followed by visibility (1.7%).
Does the 2020 GLA get worse with mileage?
Its MOT fail rate rises from 5.1% in the 0-30k band to 6.9% in the 90-120k band.
Methodology & source. Based on 29,696 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.