2018 Audi A6 — MOT failures & pass rate
The 2018 Audi A6 passed 90.9% of its 46,437 recorded MOT tests. That is 1.7 percentage points better than executive cars of a similar age, which fail at 10.8%. Failures cluster in tyres, lighting & signalling and brakes.
What the MOT record shows
Tyres dominates the failure mix at 5.8% of all tests — 4.3 points clear of lighting & signalling, so it is the first thing to check.
At component level the recurring items are tread depth, headlamp aim and brake pads — tread depth alone was recorded 1,512 times.
Mileage matters less than usual here: the 2018 A6 fails 6.7% of the time in the 0-30k band and 9.8% at 150k+, a spread of only 3.1 points.
Fuel type barely separates them — diesel fails 9.1% of the time against 9.2% for petrol.
Advisories point at the next bill rather than this one: tyres was flagged on 21.4% of tests without failing them.
The trend is worsening — 8.6% of tests failed in 2021 against 11.0% in 2025, the usual pattern as a fleet ages.
How it compares
Top failure categories
| # | Category | % of tests affected | Tests |
|---|---|---|---|
| 1 | Tyres | 5.8% | 2,693 |
| 2 | Lighting & signalling | 1.5% | 698 |
| 3 | Brakes | 1.3% | 606 |
| 4 | Visibility | 1.0% | 462 |
| 5 | Emissions & environmental | 0.9% | 435 |
| 6 | Suspension | 0.8% | 367 |
Most common specific failures
The exact components most often recorded as failures — more specific than the categories above.
| # | Failure item | Times recorded |
|---|---|---|
| 1 | Tread depth | 1,512 |
| 2 | Headlamp aim | 583 |
| 3 | Brake pads | 564 |
| 4 | Malfunction indicator lamp | 406 |
| 5 | Registration plates | 281 |
| 6 | Washers | 243 |
Top advisory categories
Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.
| # | Category | % of tests with advisory | Tests |
|---|---|---|---|
| 1 | Tyres | 21.4% | 9,944 |
| 2 | Brakes | 10.8% | 4,991 |
| 3 | Other defects | 7.3% | 3,382 |
| 4 | Suspension | 4.6% | 2,122 |
| 5 | Visibility | 3.6% | 1,684 |
| 6 | Body, structure & corrosion | 0.4% | 174 |
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 | 9,531 | 6.7% |
| 30-60k | 21,802 | 8.9% |
| 60-90k | 10,749 | 10.5% |
| 90-120k | 3,121 | 11.8% |
| 120-150k | 835 | 13.1% |
| 150k+ | 396 | 9.8% |
Failure rate by age
By fuel type
| Fuel | Tests | Fail rate |
|---|---|---|
| Diesel | 34,632 | 9.1% |
| Petrol | 11,805 | 9.2% |
Trend over time
| Dataset year | Tests | Fail rate |
|---|---|---|
| 2021 | 9,852 | 8.6% |
| 2022 | 9,437 | 7.6% |
| 2023 | 9,116 | 8.6% |
| 2024 | 9,063 | 9.9% |
| 2025 | 8,969 | 11.0% |
What to check before buying a 2018 A6
On a 2018 A6, tyres is what the MOT record says goes wrong most — it appeared in 5.8% of tests. Check these areas before you commit.
- Tyres (5.8% 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.
- Lighting & signalling (1.5% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.
- Brakes (1.3% 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 2018 Audi A6s pass their MOT?
90.9% of the 46,437 2018 Audi A6 MOT tests in this dataset passed — a 9.1% fail rate.
What is the most common MOT failure on a 2018 Audi A6?
Tyres, recorded in 5.8% of tests, followed by lighting & signalling (1.5%).
Does the 2018 A6 get worse with mileage?
Its MOT fail rate rises from 6.7% in the 0-30k band to 9.8% in the 150k+ band.
Methodology & source. Based on 46,437 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.