2004 Audi A4 — MOT failures & pass rate
Across 54,779 MOT tests analysed for the 2004 Audi A4, the most common recorded failure areas were lighting & signalling, suspension and brakes. Its pass rate of 74.0% was below the average for executive cars of a similar age (75.4%). Higher-mileage examples failed more often — 27.5% in the 150k+ group versus 18.3% in the 0-30k group.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 16.0% | 8,737 |
| 2 | Suspension | 12.3% | 6,732 |
| 3 | Brakes | 11.0% | 6,034 |
| 4 | Tyres | 6.3% | 3,443 |
| 5 | Emissions & environmental | 5.8% | 3,172 |
| 6 | Body, structure & corrosion | 5.2% | 2,859 |
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 | 3,713 |
| 2 | Pins and bushes | 3,520 |
| 3 | Headlamp | 2,593 |
| 4 | Flexible brake hoses | 2,290 |
| 5 | Position lamp | 2,100 |
| 6 | Joints | 2,087 |
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 | 40.7% | 22,292 |
| 2 | Brakes | 29.7% | 16,251 |
| 3 | Tyres | 28.4% | 15,538 |
| 4 | Lighting & signalling | 21.2% | 11,600 |
| 5 | Emissions & environmental | 19.6% | 10,728 |
| 6 | Other defects | 11.8% | 6,450 |
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 | 224 | 18.3% |
| 30-60k | 1,411 | 17.4% |
| 60-90k | 5,380 | 22.0% |
| 90-120k | 10,973 | 25.1% |
| 120-150k | 12,941 | 26.8% |
| 150k+ | 23,794 | 27.5% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Diesel | 30,951 | 26.9% |
| Petrol | 23,819 | 24.9% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 16,465 | 26.5% |
| 2022 | 13,339 | 25.9% |
| 2023 | 10,568 | 25.8% |
| 2024 | 8,160 | 26.4% |
| 2025 | 6,247 | 24.9% |
What to check before buying a 2004 A4
Before buying a 2004 Audi A4, focus on the areas it most often fails on. Lighting & signalling accounted for 16.0% of tests for this year.
- Lighting & signalling (16.0% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Suspension (12.3% 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 (11.0% 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 Audi A4s pass their MOT?
74.0% of the 54,779 2004 Audi A4 MOT tests in this dataset passed — a 26.0% fail rate.
What is the most common MOT failure on a 2004 Audi A4?
Lighting & signalling, recorded in 16.0% of tests, followed by suspension (12.3%).
Does the 2004 A4 get worse with mileage?
Its MOT fail rate rises from 18.3% in the 0-30k band to 27.5% in the 150k+ band.
Methodology & source. Based on 54,779 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.