I've done plenty of research but can't find the answer so it seems no one has had the same problem. Can anyone help me out please? It's becoming extremely frustrating as I've had the unit in for a couple of weeks now without it working properly. I've put the RNS-E into my 2004 (B6) S4 with this harness and it works independently from the car - but I get no illumination or DIS information and it doesn't power on and off at the accessory position, even after coding modules 37 and 17. I checked for fault codes and there is no CAN bus signal so the car doesnât recognise the head unit. I had a go at tracing the wires. It's difficult because there's two of nearly every coloured wire and they're hidden by binding between the connectors so I can't properly trace a wire without stripping the binding down. The CAN bus wires coming out of the RNS-E harness were blue and grey/black. There were two of each colour the other side of the binding but I noticed one of each colour's pin had the green circled wires (in the photo below) coming out the back of the car's connector. I suspect these are the CAN bus wires from a previous owner's install. If I have to do something with these (i.e., connect them to two pins in the 26-pin black/green connector) then I'm a little perplexed since it's supposed to be 'plug & play'.