ECU issues

[volksdude]

Won't get into too much details but been struggling with a 2007 RS4 wich won't start and won't communicate with ecu. Well it does communicate with slave if only 1 ecu is hooked up and this regardless of it's position wich got me thinking the issue is both ecu are seen as slave. After reading and researching a lot I found out that voltage must me applied to a specific pin on the master to tell him it's the master so now I am asking if someone could tell me wich pin is it or even better provide me with diagram and/or info about how this is done this would make my week a little less shitty