2004 Audi A6 — MOT failures & pass rate
Across 8,982 MOT tests, the 2004 Audi A6 recorded a 74.9% pass rate. That is effectively the same as executive cars of a similar age (24.3% fail rate), so the MOT record here is unremarkable in either direction. Failures cluster in lighting & signalling, suspension and brakes.
What the MOT record shows
One area stands out: lighting & signalling, recorded in 16.3% of tests against 10.0% for the next-worst category.
At component level the recurring items are headlamp aim, joints and pins and bushes — headlamp aim alone was recorded 822 times.
Mileage is the strongest signal on the record: 17.7% of 30-60k cars fail, rising to 26.8% once past 150k.
The petrol cars hold up better: 21.7% fail against 26.2% for diesel, a 4.5-point gap across 8,982 tests.
Suspension is the most common advisory, noted on 35.9% of tests — work that passed today but is likely due soon.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 16.3% | 1,461 |
| 2 | Suspension | 10.0% | 900 |
| 3 | Brakes | 9.2% | 830 |
| 4 | Body, structure & corrosion | 7.8% | 701 |
| 5 | Tyres | 5.8% | 517 |
| 6 | Emissions & environmental | 5.0% | 446 |
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 | 822 |
| 2 | Joints | 560 |
| 3 | Pins and bushes | 502 |
| 4 | Headlamp | 492 |
| 5 | Position lamp | 423 |
| 6 | Ball joint | 293 |
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 | 35.9% | 3,221 |
| 2 | Brakes | 31.6% | 2,843 |
| 3 | Tyres | 26.6% | 2,388 |
| 4 | Lighting & signalling | 18.4% | 1,648 |
| 5 | Emissions & environmental | 16.0% | 1,436 |
| 6 | Body, structure & corrosion | 12.6% | 1,132 |
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 | 192 | 17.7% |
| 60-90k | 602 | 18.8% |
| 90-120k | 1,452 | 23.7% |
| 120-150k | 2,023 | 25.0% |
| 150k+ | 4,685 | 26.8% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Diesel | 6,860 | 26.2% |
| Petrol | 2,122 | 21.7% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 2,756 | 25.3% |
| 2022 | 2,187 | 25.7% |
| 2023 | 1,734 | 23.9% |
| 2024 | 1,326 | 26.2% |
| 2025 | 979 | 24.2% |
What to check before buying a 2004 A6
The failure pattern for this year is specific enough to inspect against: lighting & signalling accounted for 16.3% of tests. Start there.
- Lighting & signalling (16.3% 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.
- Brakes (9.2% 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 A6s pass their MOT?
74.9% of the 8,982 2004 Audi A6 MOT tests in this dataset passed — a 25.1% fail rate.
What is the most common MOT failure on a 2004 Audi A6?
Lighting & signalling, recorded in 16.3% of tests, followed by suspension (10.0%).
Does the 2004 A6 get worse with mileage?
Its MOT fail rate rises from 17.7% in the 30-60k band to 26.8% in the 150k+ band.
Methodology & source. Based on 8,982 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.