Audi A4 S Line TDI (2009)
2009 Audi A4 S Line TDI
CarHunch analysed 553 real MOT records for the 2009 Audi A4 S Line TDI. This breakdown of actual test outcomes — pass rates, defect profiles, mileage data — isn't published anywhere else.
This 2009 Audi A4 S Line TDI diesel is a reliability concern: only 59.1% pass their MOT first time, significantly below the UK average of 80%, and owners are logging an average of 1.02 failures per vehicle. The good news is that dangerous defects are extremely rare at 0%, so while these cars need more maintenance work, they're not failing for safety-critical reasons.
With a median mileage of 138,108 miles for a 15-year-old car, these examples are running hard but not unusually so. The near-zero advisory count suggests that when this engine and chassis do develop faults, they tend to be definitive failures rather than emerging problems—meaning you'll face bills for worn components rather than warning signs to ignore. If you're considering one, budget for a pre-purchase inspection by a diesel specialist and expect regular maintenance costs; these aren't cars to buy cheap and hope for the best.
What to check before buying a 2009 Audi A4 S Line TDI
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 A4 S Line TDI
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 (99%) | 546 | 58.9% | 1.02 |
| Gas Bi-Fuel (1%) | 7 | 78.3% | 1.14 |
Mileage Distribution
Most 2009 Audi A4 S Line TDI 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 2009 Audi A4 S Line TDI vehicles fall between 119,032 and 155,443 miles.
2009 Audi A4 S Line TDI — Still on the Road
195 vehicles still getting MOTs in 2025 — 58% of the peak remain.
Based on vehicles from this manufacture year that had at least one MOT test in each calendar year. Data from 2017–2025.
MOT History Averages
Found a specific Audi A4 S Line TDI?
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