My car won't start. on 2004 Audi A6 Quattro

The EPC and battery icons come on. The battery is fully charged. The starter turns over but the engine won't fire.

Asked by for the 2004 Audi A6 Quattro
In my case, the problem was failure due to the High Pressure Fuel Pump. You've got the usual fuel pump but direct injections have another fuel pump to get the fuel into the cylinder. Part is around $300; labor was around $450. They have to remove some cooling system pieces to get to it so expect some additional part cost.