Hello,
I have a 2000 A4 that recently would not start it cranks over just fine but that's all it does. It also has no instrument lights and the power windows do not work. Up until this point there has been no problems at all with the car. I have read that it could be the cam position sensor (but that doesn't make sense as to why the instruments and the windows don't work) also possibly the ignition switch. Just wondering if anyone has had any similar problems or a direction to look. I checked the fuses for the ECU and the fuel pump all three had no power with the key in the on position and cranking the car over. From what I have read is that there will be no power to the fuel pump unless the car is running.
Thanks for the help, Mark

 

I'd chase after the power issues before throwing any parts at the engine. Unfortunately I don't have any electrical diagrams on the A4's so I'm not going to be any help.