2018 Mercedes-Benz GLA — MOT failures & pass rate
The 2018 Mercedes-Benz GLA passed 90.7% of its 90,246 recorded MOT tests. Small SUVs of a similar age fail at 9.9%, so the 2018 GLA sits squarely on the average. Failures cluster in tyres, lighting & signalling and visibility.
What the MOT record shows
No single area dominates — tyres (4.2%) and lighting & signalling (2.3%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are tread depth, brake pads and headlamp aim — tread depth alone was recorded 1,950 times.
A 150k+ example is materially riskier than a 0-30k one: 19.1% versus 5.9%.
Fuel type barely separates them — diesel fails 9.0% of the time against 9.6% for petrol.
Advisories point at the next bill rather than this one: tyres was flagged on 23.0% of tests without failing them.
The trend is worsening — 6.3% of tests failed in 2021 against 13.3% in 2025, the usual pattern as a fleet ages.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 4.2% | 3,806 |
| 2 | Lighting & signalling | 2.3% | 2,099 |
| 3 | Visibility | 2.2% | 2,018 |
| 4 | Brakes | 1.9% | 1,715 |
| 5 | Body, structure & corrosion | 1.5% | 1,323 |
| 6 | Emissions & environmental | 0.9% | 816 |
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 | 1,950 |
| 2 | Brake pads | 1,658 |
| 3 | Headlamp aim | 1,405 |
| 4 | Joints | 1,303 |
| 5 | Washers | 1,147 |
| 6 | Wipers | 1,095 |
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 | 23.0% | 20,771 |
| 2 | Brakes | 13.6% | 12,272 |
| 3 | Other defects | 7.5% | 6,768 |
| 4 | Visibility | 2.5% | 2,273 |
| 5 | Lighting & signalling | 2.2% | 2,005 |
| 6 | Suspension | 1.6% | 1,434 |
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 | 35,220 | 5.9% |
| 30-60k | 42,838 | 10.4% |
| 60-90k | 10,407 | 14.9% |
| 90-120k | 1,499 | 16.9% |
| 120-150k | 222 | 16.7% |
| 150k+ | 47 | 19.1% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Petrol | 47,291 | 9.6% |
| Diesel | 42,955 | 9.0% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 17,996 | 6.3% |
| 2022 | 17,658 | 6.6% |
| 2023 | 17,887 | 9.0% |
| 2024 | 18,075 | 11.1% |
| 2025 | 18,630 | 13.3% |
What to check before buying a 2018 GLA
On a 2018 GLA, tyres is what the MOT record says goes wrong most — it appeared in 4.2% of tests. Check these areas before you commit.
- Tyres (4.2% 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.
- Lighting & signalling (2.3% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Visibility (2.2% 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 2018 Mercedes-Benz GLAs pass their MOT?
90.7% of the 90,246 2018 Mercedes-Benz GLA MOT tests in this dataset passed — a 9.3% fail rate.
What is the most common MOT failure on a 2018 Mercedes-Benz GLA?
Tyres, recorded in 4.2% of tests, followed by lighting & signalling (2.3%).
Does the 2018 GLA get worse with mileage?
Its MOT fail rate rises from 5.9% in the 0-30k band to 19.1% in the 150k+ band.
Methodology & source. Based on 90,246 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.