Audi A6 S Line TDI Ultra S A (2015)
2015 Audi A6 S Line TDI Ultra S A
CarHunch analysed 729 real MOT records for the 2015 Audi A6 S Line TDI Ultra S A. This breakdown of actual test outcomes — pass rates, defect profiles, mileage data — isn't published anywhere else.
This 2015 Audi A6 S Line TDI Ultra is a significant reliability concern: only 51.4% pass their MOT first time, well below the 80% UK average, which means roughly half of these cars fail their first test. The good news is that dangerous defects are virtually absent (0%), so safety isn't the issue—the failures are likely wear-related problems on a nine-year-old diesel saloon.
With a median mileage of 90,825 miles for vehicles this age, these A6s are running at typical wear levels, yet the 0.16 average failures per car suggest common maintenance costs are coming up across the cohort. Before buying one, get a thorough pre-purchase inspection from a diesel-specialist mechanic, paying close attention to the DPF, injectors, and transmission—the typical weak points on ageing TDI models that drive these MOT failure rates.
What to check before buying a 2015 Audi A6 S Line TDI Ultra S A
Practical pre-purchase checks for this age and model.
- 📋 Check the full MOT history. Look for recurring advisories — slow-building issues like corrosion or brake wear patterns show up years before they become failures. Enter the reg below for a full AI analysis.
- 🔍 Inspect for corrosion in person. Brake pipes, sills, subframes, and chassis legs. Surface rust is normal at this age; structural rust is a serious problem that's expensive to fix and can fail an MOT.
- 🛞 Check tyres and brakes. The most common advisory items at this age. Budget for replacement if they're near the limit — factor this into your offer price.
- 📄 Run an HPI check. The MOT history won't show outstanding finance, insurance write-offs, or stolen status — an HPI check will.
Before you buy a Audi A6 S Line TDI Ultra S A
MOT history is one piece of the puzzle. These checks can reveal what CarHunch can't.
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Pass Rate by Fuel Type
| Fuel type | Vehicles | Pass rate | Avg failures |
|---|---|---|---|
| Diesel (100%) | 728 | 51.4% | 0.16 |
| Gas Bi-Fuel (0%) | 1 | 100% | 0 |
Mileage Distribution
Most 2015 Audi A6 S Line TDI Ultra S A vehicles sit in the blue band. If the car you're looking at is outside it, it's either unusually low or high mileage for its age.
Half of all 2015 Audi A6 S Line TDI Ultra S A vehicles fall between 75,770 and 109,835 miles.
2015 Audi A6 S Line TDI Ultra S A — Still on the Road
Strong survival — 280 vehicles still getting MOTs in 2025, 100% of the peak.
Based on vehicles from this manufacture year that had at least one MOT test in each calendar year. Data from 2019–2025.
MOT History Averages
Found a specific Audi A6 S Line TDI Ultra S A?
Enter the reg to see its individual MOT history, AI Hunches, and how it compares to this cohort.