2020 Mercedes-Benz GLC — MOT failures & pass rate
Across 37,137 MOT tests, the 2020 Mercedes-Benz GLC recorded a 92.6% pass rate. Against mid-size SUVs of a similar age (8.8% fail rate), the 2020 GLC comes out 1.4pp better. Failures cluster in tyres, brakes and visibility.
What the MOT record shows
One area stands out: tyres, recorded in 4.8% of tests against 1.3% for the next-worst category.
At component level the recurring items are tread depth, brake pads and headlamp aim — tread depth alone was recorded 653 times.
Mileage is the strongest signal on the record: 5.7% of 0-30k cars fail, rising to 16.7% once past 120-150k — 2.9× the risk.
The hybrid cars hold up better: 5.9% fail against 8.1% for petrol, a 2.1-point gap across 10,414 tests.
Tyres is the most common advisory, noted on 21.0% of tests — work that passed today but is likely due soon.
The trend is worsening — 2.5% of tests failed in 2022 against 8.2% in 2025, the usual pattern as a fleet ages.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 4.8% | 1,780 |
| 2 | Brakes | 1.3% | 465 |
| 3 | Visibility | 1.1% | 397 |
| 4 | Suspension | 1.0% | 359 |
| 5 | Lighting & signalling | 0.9% | 340 |
| 6 | Other defects | 0.4% | 132 |
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 | 653 |
| 2 | Brake pads | 486 |
| 3 | Headlamp aim | 372 |
| 4 | Ball joint | 368 |
| 5 | Wipers | 235 |
| 6 | Registration plates | 219 |
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 | 21.0% | 7,789 |
| 2 | Brakes | 9.2% | 3,409 |
| 3 | Other defects | 6.3% | 2,353 |
| 4 | Visibility | 3.3% | 1,217 |
| 5 | Suspension | 3.2% | 1,198 |
| 6 | Lighting & signalling | 0.4% | 132 |
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 | 15,873 | 5.7% |
| 30-60k | 18,199 | 8.5% |
| 60-90k | 2,724 | 10.0% |
| 90-120k | 289 | 9.7% |
| 120-150k | 42 | 16.7% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Diesel | 26,717 | 7.8% |
| Hybrid | 8,242 | 5.9% |
| Petrol | 2,172 | 8.1% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2022 | 366 | 2.5% |
| 2023 | 12,601 | 6.6% |
| 2024 | 12,203 | 7.6% |
| 2025 | 11,951 | 8.2% |
What to check before buying a 2020 GLC
The failure pattern for this year is specific enough to inspect against: tyres accounted for 4.8% of tests. Start there.
- Tyres (4.8% 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 (1.3% 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.
- Visibility (1.1% 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.
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 GLCs pass their MOT?
92.6% of the 37,137 2020 Mercedes-Benz GLC MOT tests in this dataset passed — a 7.4% fail rate.
What is the most common MOT failure on a 2020 Mercedes-Benz GLC?
Tyres, recorded in 4.8% of tests, followed by brakes (1.3%).
Does the 2020 GLC get worse with mileage?
Its MOT fail rate rises from 5.7% in the 0-30k band to 16.7% in the 120-150k band.
Methodology & source. Based on 37,137 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.