2004 Mercedes-Benz Viano — MOT failures & pass rate
The 2004 Mercedes-Benz Viano passed 75.0% of its 1,725 recorded MOT tests. All cars of a similar age fail 27.7% of the time, so this is 2.7pp better than the group it competes with. Failures cluster in lighting & signalling, suspension and brakes.
What the MOT record shows
Lighting & signalling dominates the failure mix at 17.0% of all tests — 5.0 points clear of suspension, so it is the first thing to check.
At component level the recurring items are component mounting prescribed areas, headlamp aim and headlamp — component mounting prescribed areas alone was recorded 218 times.
Mileage is the strongest signal on the record: 30.6% of 0-30k cars fail, rising to 26.3% once past 150k.
Split by fuel, diesel examples fail 6.5pp more often than petrol ones (27.4% vs 20.9%) — worth weighing if you have a choice.
Advisories point at the next bill rather than this one: brakes was flagged on 36.2% of tests without failing them.
The trend is improving — the fail rate fell from 28.1% in 2021 to 24.4% in 2025, as the worst-kept examples leave the fleet.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 17.0% | 293 |
| 2 | Suspension | 11.9% | 206 |
| 3 | Brakes | 9.9% | 171 |
| 4 | Body, structure & corrosion | 8.3% | 143 |
| 5 | Seat belts & restraints | 6.4% | 111 |
| 6 | Visibility | 5.7% | 98 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Component mounting prescribed areas | 218 |
| 2 | Headlamp aim | 150 |
| 3 | Headlamp | 118 |
| 4 | Integral vehicle structure condition | 101 |
| 5 | Rigid brake pipes | 81 |
| 6 | SRS malfunction indicator lamp | 75 |
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 | 36.2% | 624 |
| 2 | Tyres | 24.5% | 423 |
| 3 | Suspension | 23.4% | 404 |
| 4 | Lighting & signalling | 20.8% | 358 |
| 5 | Body, structure & corrosion | 16.3% | 281 |
| 6 | Emissions & environmental | 10.8% | 187 |
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 | 72 | 30.6% |
| 30-60k | 273 | 16.9% |
| 60-90k | 288 | 23.3% |
| 90-120k | 257 | 24.9% |
| 120-150k | 265 | 27.6% |
| 150k+ | 495 | 26.3% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Diesel | 1,088 | 27.4% |
| Petrol | 637 | 20.9% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 327 | 28.1% |
| 2022 | 405 | 24.7% |
| 2023 | 371 | 24.0% |
| 2024 | 327 | 23.8% |
| 2025 | 295 | 24.4% |
What to check before buying a 2004 Viano
On a 2004 Viano, lighting & signalling is what the MOT record says goes wrong most — it appeared in 17.0% of tests. Check these areas before you commit.
- Lighting & signalling (17.0% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Suspension (11.9% 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 (9.9% 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 2004 Mercedes-Benz Vianos pass their MOT?
75.0% of the 1,725 2004 Mercedes-Benz Viano MOT tests in this dataset passed — a 25.0% fail rate.
What is the most common MOT failure on a 2004 Mercedes-Benz Viano?
Lighting & signalling, recorded in 17.0% of tests, followed by suspension (11.9%).
Does the 2004 Viano get worse with mileage?
Its MOT fail rate rises from 30.6% in the 0-30k band to 26.3% in the 150k+ band.
Methodology & source. Based on 1,725 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.