I have a 2007 Audi RS4; it usually refuses to start when I leave it to cool down. The agents have changed the starter relay and it still does the same thing. The starter doesn’t turn and I can only hear the clicking sound from the relay. I usually press the starter button continuously for about 30 minutes until it starts.
Audi No Start
Well this particular vehicle has 2 starter relays. You may need to replace both of them. However you can do a little testing. Next time it will not start you can check for battery voltage at the “S” terminal when someone holds the start button. If you see battery voltage, replace the starter. If not you may need to trace the wiring or replace a relay or ignition switch.