New listing 2012 AUDI A6 Allroad 3.0 TDI Quattro Estate Auto - Black Leather - 148,000 Miles. 2006 Audi A6 C6 2.0tdi S-line Estate. Mot - 10 Months. £1,600.00. Plug in the connection cable and then start the VCDS app. Choose the following path: Engine > Basic Settings > 140 for group > "ON". The pressurized indicator will drop to zero, then shut the engine off. Pull the fuel pump fuse. Attempt to start the car until it completely stalls. Audi A6 C6 2006 3.0 quattro. 4 250 VAND SAU SCHIMB 2006 Audi A6 C6 Quattro 3.0 TDI 225 CP. 3 500 € Step 3 – Check your vacuum lines and master cylinder. Air and fluid leaks can lead to major issues. A bad master cylinder can cause your brake pedal to go all the way to the floor with little or no pressure. Similarly, a leak in the vacuum system can cause a hard pedal. Inspect the master cylinder for leaks. Check all of the vacuum lines rkER.