Hi. I just got an 2006 A4 Quattro. I bought an aftermarket radio but havn't had it installed yet. Someone had mentioned to me that the diagnostics for the car runs thru the stock radio and installing an aftermarket can cause problems. I purchased the wiring harness for my car (metra harness #70-1787) as well as the Metra steering wheel control harness. The radio is a Kenwood DDX-371. I'd like to get the radio installed this weekend so uf anyone can let me know of any known problems please help me out.. Thank you

 

Hi.
Yes the diagnostics are connected to the factory fit stereo, however it is for the purposes of communicating with the stereo to diagnose any faults with it. So at worst replacing it with a non-audi unit would only mean that the cars diagnostics can't talk to the unit but this shouldn't interfere with the diag link to the other systems on the vehicle.

 

Ok.. Thank you!