2012 Mercedes-Benz G-Class — MOT failures & pass rate
Across 595 MOT tests, the 2012 Mercedes-Benz G-Class recorded an 85.5% pass rate. Large SUVs of a similar age fail 17.8% of the time, so this is 3.4pp better than the group it competes with. Failures cluster in lighting & signalling, brakes and emissions & environmental.
What the MOT record shows
No single area dominates — lighting & signalling (5.5%) and brakes (5.2%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are rigid brake pipes, malfunction indicator lamp and individual direction indicators — rigid brake pipes alone was recorded 29 times.
A 120-150k example is materially riskier than a 0-30k one: 20.0% versus 7.8%.
Advisories point at the next bill rather than this one: brakes was flagged on 19.8% of tests without failing them.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 5.5% | 33 |
| 2 | Brakes | 5.2% | 31 |
| 3 | Emissions & environmental | 3.5% | 21 |
| 4 | Tyres | 2.7% | 16 |
| 5 | Steering | 2.0% | 12 |
| 6 | Suspension | 1.8% | 11 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Rigid brake pipes | 29 |
| 2 | Malfunction indicator lamp | 20 |
| 3 | Individual direction indicators | 14 |
| 4 | Headlamp aim | 13 |
| 5 | Tread depth | 9 |
| 6 | Registration plates | 8 |
Top advisory categories
Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.
| # | Category | % of tests with advisory | Tests |
|---|---|---|---|
| 1 | Brakes | 19.8% | 118 |
| 2 | Tyres | 13.5% | 80 |
| 3 | Emissions & environmental | 10.1% | 60 |
| 4 | Suspension | 7.1% | 42 |
| 5 | Steering | 6.6% | 39 |
| 6 | Lighting & signalling | 4.5% | 27 |
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 | 51 | 7.8% |
| 30-60k | 155 | 11.0% |
| 60-90k | 186 | 13.4% |
| 90-120k | 143 | 19.6% |
| 120-150k | 50 | 20.0% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Diesel | 444 | 16.7% |
| Petrol | 151 | 8.0% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 126 | 14.3% |
| 2022 | 117 | 10.3% |
| 2023 | 128 | 16.4% |
| 2024 | 113 | 15.9% |
| 2025 | 111 | 15.3% |
What to check before buying a 2012 G-Class
On a 2012 G-Class, lighting & signalling is what the MOT record says goes wrong most — it appeared in 5.5% of tests. Check these areas before you commit.
- Lighting & signalling (5.5% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Brakes (5.2% 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.
- Emissions & environmental (3.5% of tests): More common on older diesels (DPF/EGR) — can be expensive; check for warning lights and smoke. Typical repair: £100–£600.
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 2012 Mercedes-Benz G-Classs pass their MOT?
85.5% of the 595 2012 Mercedes-Benz G-Class MOT tests in this dataset passed — a 14.4% fail rate.
What is the most common MOT failure on a 2012 Mercedes-Benz G-Class?
Lighting & signalling, recorded in 5.5% of tests, followed by brakes (5.2%).
Does the 2012 G-Class get worse with mileage?
Its MOT fail rate rises from 7.8% in the 0-30k band to 20.0% in the 120-150k band.
Methodology & source. Based on 595 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.