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Hello everybody,
I have recently become the proud owner of a B5 S4, silver with white silk leather. The only mods i've done so far (if you even want to call them mods) is a RS4 grille and shift knob. However, i have become very interested in installing a RNS-E in my ride. I have done alot of reading and determined that the closest thing to fitting is a unit from the new A6.

I still have some questions thoough. I've been searching all over for an accurate step-by step installation on a B5 S4 but haven't been able to find one. Especialy one that explains what the CAN Bus is...and what i need to do to make everything work right. I also dont know of any solid sources to buy a RNS-E or a list of exactialy what i will need to make the whole installation process as easy as possible! :lol: (i try to steer clear of ebay...long story... :x ). I also don't really know the easiest way to modify the faceplale to fit nice in the dash.

i have more questions but will save them for later! Any help will be greatly appreciated!! Thanks again.
 

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I will try to answer the CAN-Bus question, the other answers are already posted here and there and you will find them if you browse through the various discussions/forums.

Audi introduced the Controller Area Network (CAN) in early MY 2000, starting with the engine and moving on to more areas. The goal was to reduce the number of wires as more little electronic toys became standard. In todays A4 B7 for example, all lights are CAN enabled and you can program individual functions instead of changing wires (e.g. daytime running lights, auto check control, etc., coming home). There are currently 3 different CAN busses in the A3/A4, the engine/drive train, the display and the infotainment CAN. They operate at different speeds and are connected via a gateway. This way devices on one bus can talk to devices on a different bus.

In the old days there were separate wires for ingition (KL 15), light (KL 58), speed (GALA), reverse and a date/time signal, besides the mandatory 12V+ (KL 30) and ground (KL 31). The A4/S4 B5 has those signals on the CAN (if present), except for the speed signal and the date/time. The A6 C5 is only missing the speed signal, unless it's a pre-facelift which is also missing the date/time signal. The A4 B6/B7 and A3 8P have all required signals on the CAN which makes the RNS-E install very easy and straight forward.

The RNS-E requires the display CAN which is usually present if the car has a digital clock in the instrument cluster. Early radios had no use for the display CAN, therefore the wires are not present in the radio plug. But the instrument cluster has pins for those CAN wires, that's were the B5 guys get the display CAN for the RNS-E even though CAN is not used for anything else.

So what does this mean to you?

If your B5 is pre-facelift (analogue clock in instrument cluster) you must get an expensive CAN-Bus adapter which translates the analogue signals for light/ignition/speed into CAN signals. If you have a facelift B5 with CAN you may be lucky and have only to deal with getting the wires from behind the instrument cluster (and live with the fact that your cluster and your RNS-E cannot agree on the arrival time).

Have fun...
 
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