1998 Audi A6 — MOT failures & pass rate
Across 636 MOT tests, the 1998 Audi A6 recorded a 73.6% pass rate. That is 3.5 percentage points worse than executive cars of a similar age, which fail at 22.9%. Failures cluster in lighting & signalling, suspension and body, structure & corrosion.
What the MOT record shows
Lighting & signalling dominates the failure mix at 14.5% of all tests — 3.1 points clear of suspension, so it is the first thing to check.
At component level the recurring items are joints, headlamp and catalyst emissions — joints alone was recorded 40 times.
Condition tracks the odometer closely. Failures run at 12.9% in the 60-90k band and 28.2% in the 150k+ band, a 15.3-point spread — more than double.
Advisories point at the next bill rather than this one: suspension was flagged on 35.5% of tests without failing them.
The trend is improving — the fail rate fell from 30.0% in 2021 to 19.4% in 2025, as the worst-kept examples leave the fleet.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Lighting & signalling | 14.5% | 92 |
| 2 | Suspension | 11.3% | 72 |
| 3 | Body, structure & corrosion | 8.8% | 56 |
| 4 | Brakes | 7.4% | 47 |
| 5 | Steering | 7.1% | 45 |
| 6 | Emissions & environmental | 6.0% | 38 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Joints | 40 |
| 2 | Headlamp | 36 |
| 3 | Catalyst emissions | 32 |
| 4 | Ball joint | 32 |
| 5 | Headlamp aim | 32 |
| 6 | Pins and bushes | 29 |
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 | 35.5% | 226 |
| 2 | Brakes | 35.5% | 226 |
| 3 | Emissions & environmental | 30.8% | 196 |
| 4 | Tyres | 25.0% | 159 |
| 5 | Lighting & signalling | 16.5% | 105 |
| 6 | Body, structure & corrosion | 14.6% | 93 |
Failure rate by mileage
Higher-mileage cars tend to fail more — often the most useful guide to real condition.
| Mileage band | Tests | Fail rate |
|---|---|---|
| 60-90k | 31 | 12.9% |
| 90-120k | 136 | 27.9% |
| 120-150k | 131 | 24.4% |
| 150k+ | 315 | 28.2% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Petrol | 470 | 26.4% |
| Diesel | 166 | 26.5% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 210 | 30.0% |
| 2022 | 158 | 27.2% |
| 2023 | 119 | 24.4% |
| 2024 | 82 | 24.4% |
| 2025 | 67 | 19.4% |
What to check before buying a 1998 A6
On a 1998 A6, lighting & signalling is what the MOT record says goes wrong most — it appeared in 14.5% of tests. Check these areas before you commit.
- Lighting & signalling (14.5% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Suspension (11.3% 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.
- Body, structure & corrosion (8.8% of tests): The one to take seriously on older cars — corrosion to structural areas can be costly and is an MOT failure. Typical repair: £200–£1,500+.
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 1998 Audi A6s pass their MOT?
73.6% of the 636 1998 Audi A6 MOT tests in this dataset passed — a 26.4% fail rate.
What is the most common MOT failure on a 1998 Audi A6?
Lighting & signalling, recorded in 14.5% of tests, followed by suspension (11.3%).
Does the 1998 A6 get worse with mileage?
Its MOT fail rate rises from 12.9% in the 60-90k band to 28.2% in the 150k+ band.
Methodology & source. Based on 636 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.