2009 Mercedes-Benz 320 — MOT failures & pass rate
Across 258 MOT tests, the 2009 Mercedes-Benz 320 recorded a 72.5% pass rate. That is 2.2 percentage points worse than all cars of a similar age, which fail at 25.4%. Failures cluster in suspension, lighting & signalling and brakes.
What the MOT record shows
No single area dominates — suspension (14.7%) and lighting & signalling (13.2%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are ball joint, rigid brake pipes and headlamp aim — ball joint alone was recorded 21 times.
A 150k+ example is materially riskier than a 60-90k one: 31.7% versus 25.0%.
Brakes is the most common advisory, noted on 35.3% of tests — work that passed today but is likely due soon.
The trend is worsening — 27.0% of tests failed in 2021 against 34.0% in 2025, the usual pattern as a fleet ages.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Suspension | 14.7% | 38 |
| 2 | Lighting & signalling | 13.2% | 34 |
| 3 | Brakes | 10.1% | 26 |
| 4 | Tyres | 4.3% | 11 |
| 5 | Steering | 3.9% | 10 |
| 6 | Visibility | 3.5% | 9 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Ball joint | 21 |
| 2 | Rigid brake pipes | 17 |
| 3 | Headlamp aim | 15 |
| 4 | Coil spring | 10 |
| 5 | Side repeaters | 8 |
| 6 | Tread depth | 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 | 35.3% | 91 |
| 2 | Tyres | 28.3% | 73 |
| 3 | Suspension | 25.2% | 65 |
| 4 | Emissions & environmental | 13.2% | 34 |
| 5 | Steering | 7.8% | 20 |
| 6 | Other defects | 7.0% | 18 |
Failure rate by mileage
Higher-mileage cars tend to fail more — often the most useful guide to real condition.
| Mileage band | Tests | Fail rate |
|---|---|---|
| 60-90k | 56 | 25.0% |
| 90-120k | 82 | 28.1% |
| 120-150k | 53 | 28.3% |
| 150k+ | 60 | 31.7% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 63 | 27.0% |
| 2022 | 51 | 21.6% |
| 2023 | 46 | 23.9% |
| 2024 | 51 | 31.4% |
| 2025 | 47 | 34.0% |
What to check before buying a 2009 320
The failure pattern for this year is specific enough to inspect against: suspension accounted for 14.7% of tests. Start there.
- Suspension (14.7% 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.
- Lighting & signalling (13.2% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Brakes (10.1% 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 2009 Mercedes-Benz 320s pass their MOT?
72.5% of the 258 2009 Mercedes-Benz 320 MOT tests in this dataset passed — a 27.5% fail rate.
What is the most common MOT failure on a 2009 Mercedes-Benz 320?
Suspension, recorded in 14.7% of tests, followed by lighting & signalling (13.2%).
Does the 2009 320 get worse with mileage?
Its MOT fail rate rises from 25.0% in the 60-90k band to 31.7% in the 150k+ band.
Methodology & source. Based on 258 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.