2004 Audi S4 — MOT failures & pass rate
Across 890 MOT tests, the 2004 Audi S4 recorded an 80.7% pass rate. That is 5.0 percentage points better than executive cars of a similar age, which fail at 24.3%. Failures cluster in lighting & signalling, suspension and tyres.
What the MOT record shows
No single area dominates — lighting & signalling (10.1%) and suspension (10.0%) are close, so failures are spread across several systems rather than one weak point.
At component level the recurring items are pins and bushes, headlamp aim and joints — pins and bushes alone was recorded 55 times.
Condition tracks the odometer closely. Failures run at 12.9% in the 30-60k band and 28.4% in the 150k+ band, a 15.5-point spread — more than double.
Suspension is the most common advisory, noted on 27.8% of tests — work that passed today but is likely due soon.
The trend is improving — the fail rate fell from 22.0% in 2021 to 17.6% in 2025, as the worst-kept examples leave the fleet.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 10.1% | 90 |
| 2 | Suspension | 10.0% | 89 |
| 3 | Tyres | 4.6% | 41 |
| 4 | Body, structure & corrosion | 4.4% | 39 |
| 5 | Emissions & environmental | 4.2% | 37 |
| 6 | Visibility | 3.0% | 27 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Pins and bushes | 55 |
| 2 | Headlamp aim | 39 |
| 3 | Joints | 32 |
| 4 | Coil spring | 29 |
| 5 | Ball joint dust cover | 28 |
| 6 | Headlamp | 27 |
Top advisory categories
Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.
| # | Category | % of tests with advisory | Tests |
|---|---|---|---|
| 1 | Suspension | 27.8% | 247 |
| 2 | Emissions & environmental | 25.3% | 225 |
| 3 | Tyres | 24.5% | 218 |
| 4 | Brakes | 22.5% | 200 |
| 5 | Lighting & signalling | 16.0% | 142 |
| 6 | Body, structure & corrosion | 12.9% | 115 |
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 | 70 | 12.9% |
| 60-90k | 239 | 19.7% |
| 90-120k | 346 | 18.5% |
| 120-150k | 155 | 19.4% |
| 150k+ | 74 | 28.4% |
Failure rate by age
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 209 | 22.0% |
| 2022 | 185 | 17.3% |
| 2023 | 175 | 18.9% |
| 2024 | 168 | 20.2% |
| 2025 | 153 | 17.6% |
What to check before buying a 2004 S4
The failure pattern for this year is specific enough to inspect against: lighting & signalling accounted for 10.1% of tests. Start there.
- Lighting & signalling (10.1% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Suspension (10.0% 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.
- Tyres (4.6% of tests): Usually a quick, known-cost fix, but check tread, age and uneven wear (which can hint at alignment or suspension issues). Typical repair: £50–£120 per tyre.
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 Audi S4s pass their MOT?
80.7% of the 890 2004 Audi S4 MOT tests in this dataset passed — a 19.3% fail rate.
What is the most common MOT failure on a 2004 Audi S4?
Lighting & signalling, recorded in 10.1% of tests, followed by suspension (10.0%).
Does the 2004 S4 get worse with mileage?
Its MOT fail rate rises from 12.9% in the 30-60k band to 28.4% in the 150k+ band.
Methodology & source. Based on 890 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.