Audi A6 C6 3.0 TDI, 225 PS, 6-speed automatic, all-wheel drive (2004–2006)

Research for this car

• Generation guide Audi A6 C6 (2004-2011): known problems and buying guide

  Buy with a service record. Check gearbox smoothness, the 3.0 TDI chain noise and oil use before paying.

• Gearbox guide ZF 6HP 6-speed automatic (BMW Steptronic, Audi tiptronic): problems, costs and what to check

  A workable six-speed when its fluid is changed on time, but mechatronic and bushing wear recur. Buy with service proof and a clean scan.

Known issues for this car

Before you buy this car

From the generation guide

1. Listen for a rattle on a cold start. A rattle lasting 2 to 5 seconds is a warning sign on a 3.0 TDI. Ask for chain records, and read the fault memory for codes P0016 to P0019.
2. On a 3.0 TDI, look for exhaust smoke, and check the engine oil for fuel. Fuel in the oil points to injector wear.
3. On a diesel, ask whether the particulate filter was cleaned or replaced. Diesel smell in the oil is a bad sign.

From the gearbox guide

1. Read the fault memory with ISTA or a BMW or Audi scanner. Bad result: BMW codes 4F85, 4F8F or 4F83, or a past limp mode. A scanner is needed.
2. Ask for fluid and pan service records. Bad result: no change in the last 60,000 to 100,000 km, or no adaptation reset afterwards. Dirty oil adds to mechatronic wear.
3. Drive 15 minutes in town, then under load. Bad result: slipping, flaring, or jerks on 2-3 and 3-4.
4. Hold a steady light throttle at 60 to 80 km/h. Bad result: a shudder or vibration, which points to the torque converter lock-up clutch.
5. Drive under load in 4th and 5th. Bad result: slip under load or jerks on shift, which points to worn bushings.

Running costs

ADAC figures for 15,000 km a year over 60 months

ADAC versions