2004 Vauxhall Signum — MOT failures & pass rate
The 2004 Vauxhall Signum passed 67.4% of its 1,708 recorded MOT tests. Large family cars of a similar age fail 28.0% of the time, so this is 4.7pp worse than the group it competes with. Failures cluster in suspension, lighting & signalling and brakes.
What the MOT record shows
No single area dominates — suspension (17.2%) and lighting & signalling (17.0%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are headlamp aim, joints and coil spring — headlamp aim alone was recorded 150 times.
Condition tracks the odometer closely. Failures run at 27.2% in the 30-60k band and 33.7% in the 150k+ band, a 6.5-point spread.
The diesel cars hold up better: 31.7% fail against 33.4% for petrol, a 1.7-point gap across 1,708 tests.
Brakes is the most common advisory, noted on 44.8% of tests — work that passed today but is likely due soon.
The trend is improving — the fail rate fell from 33.7% in 2021 to 29.6% in 2025, as the worst-kept examples leave the fleet.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Suspension | 17.2% | 293 |
| 2 | Lighting & signalling | 17.0% | 291 |
| 3 | Brakes | 14.9% | 254 |
| 4 | Body, structure & corrosion | 10.7% | 182 |
| 5 | Tyres | 7.5% | 129 |
| 6 | Emissions & environmental | 7.4% | 126 |
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 | 150 |
| 2 | Joints | 131 |
| 3 | Coil spring | 129 |
| 4 | Rigid brake pipes | 120 |
| 5 | Headlamp | 101 |
| 6 | Tread depth | 77 |
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 | 44.8% | 765 |
| 2 | Suspension | 36.6% | 626 |
| 3 | Tyres | 29.7% | 508 |
| 4 | Lighting & signalling | 26.4% | 450 |
| 5 | Other defects | 24.2% | 414 |
| 6 | Emissions & environmental | 20.0% | 342 |
Failure rate by mileage
Higher-mileage cars tend to fail more — often the most useful guide to real condition.
| Mileage band | Tests | Fail rate |
|---|---|---|
| 30-60k | 136 | 27.2% |
| 60-90k | 310 | 31.9% |
| 90-120k | 515 | 34.8% |
| 120-150k | 365 | 32.0% |
| 150k+ | 362 | 33.7% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Petrol | 910 | 33.4% |
| Diesel | 798 | 31.7% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 652 | 33.7% |
| 2022 | 417 | 32.6% |
| 2023 | 293 | 30.4% |
| 2024 | 211 | 34.1% |
| 2025 | 135 | 29.6% |
What to check before buying a 2004 Signum
The failure pattern for this year is specific enough to inspect against: suspension accounted for 17.2% of tests. Start there.
- Suspension (17.2% 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 (17.0% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Brakes (14.9% 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 Vauxhall Signums pass their MOT?
67.4% of the 1,708 2004 Vauxhall Signum MOT tests in this dataset passed — a 32.6% fail rate.
What is the most common MOT failure on a 2004 Vauxhall Signum?
Suspension, recorded in 17.2% of tests, followed by lighting & signalling (17.0%).
Does the 2004 Signum get worse with mileage?
Its MOT fail rate rises from 27.2% in the 30-60k band to 33.7% in the 150k+ band.
Methodology & source. Based on 1,708 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.