2012 Mercedes-Benz A-Class — MOT failures & pass rate
Across 33,415 MOT tests analysed for the 2012 Mercedes-Benz A-Class, the most common recorded failure areas were lighting & signalling, suspension and brakes. Its pass rate of 80.1% was above the average for small family cars of a similar age (78.8%). Higher-mileage examples failed more often — 27.6% in the 150k+ group versus 11.4% in the 0-30k group.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 10.6% | 3,550 |
| 2 | Suspension | 6.7% | 2,238 |
| 3 | Brakes | 6.3% | 2,122 |
| 4 | Visibility | 4.5% | 1,517 |
| 5 | Tyres | 3.9% | 1,312 |
| 6 | Emissions & environmental | 2.1% | 710 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Headlamp aim | 1,652 |
| 2 | Coil spring | 1,455 |
| 3 | Side repeaters | 1,340 |
| 4 | Washers | 1,180 |
| 5 | Brake pads | 804 |
| 6 | Rigid brake pipes | 792 |
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 | 25.7% | 8,598 |
| 2 | Tyres | 25.3% | 8,445 |
| 3 | Other defects | 9.9% | 3,315 |
| 4 | Suspension | 8.8% | 2,932 |
| 5 | Visibility | 3.8% | 1,260 |
| 6 | Body, structure & corrosion | 3.7% | 1,237 |
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 | 2,419 | 11.4% |
| 30-60k | 12,624 | 17.2% |
| 60-90k | 11,249 | 21.0% |
| 90-120k | 5,223 | 25.2% |
| 120-150k | 1,493 | 27.3% |
| 150k+ | 398 | 27.6% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Petrol | 18,280 | 19.3% |
| Diesel | 15,135 | 20.7% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 6,740 | 17.7% |
| 2022 | 6,734 | 18.3% |
| 2023 | 6,792 | 20.2% |
| 2024 | 6,665 | 21.5% |
| 2025 | 6,484 | 21.9% |
What to check before buying a 2012 A-Class
Before buying a 2012 Mercedes-Benz A-Class, focus on the areas it most often fails on. Lighting & signalling accounted for 10.6% of tests for this year.
- Lighting & signalling (10.6% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Suspension (6.7% of tests): Worn drop links, bushes, springs or shocks — listen for knocks over bumps and check for uneven tyre wear. Typical repair: £150–£450 per corner.
- Brakes (6.3% 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.
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 A-Classs pass their MOT?
80.1% of the 33,415 2012 Mercedes-Benz A-Class MOT tests in this dataset passed — a 19.9% fail rate.
What is the most common MOT failure on a 2012 Mercedes-Benz A-Class?
Lighting & signalling, recorded in 10.6% of tests, followed by suspension (6.7%).
Does the 2012 A-Class get worse with mileage?
Its MOT fail rate rises from 11.4% in the 0-30k band to 27.6% in the 150k+ band.
Methodology & source. Based on 33,415 MOT tests. Dataset: DVSA MOT testing data (2021,2022,2023,2024,2025). Data last updated 2026-07-01. Figures reflect MOT-testable defects only — read the methodology for how these are calculated and what they don't measure.