[AudiA4B6US]

It's acutally the head unit which remembers the car, not the other way around. My RNS-E was asking for the code while connected to 12V only and when I first put it in my car. Since then neither my RNS-E nor my Symphony II ask for a code.

So, as long as you don't connect it to a different car (and maybe keeping is disconnected from a car for a very long time) it should not ask for the code.

 

[AudiA4B6US]

Hard to say. I don't know how the RNS-E or other HUs get the car's signature (be it VIN or anything else). I guess the only way for this to work is to use the k-line or CAN-bus and talk to the ECU or instrument cluster. Since your RNS-E seems to act somehow strange, maybe there is something wrong. Did you do the reset (hold RADIO and SETUP for more than 10s) and do you have the newest software (sw 0100) installed?

 

[AudiA4B6US]

My RNS-E didn't even ask for the security code... maybe cuz I bought it brand new?

Now there's no way to tell since it will always recognize my car... I just wanna make sure the code works!

Mine didn't ask either at the beginning. Then after playing about two weeks with the unit being connected to just 12V+ and GND, I got the prompt out of the blue. IIRC I have read somewhere that there is some grace period for brand new devices. You either connect them to a car right away or, as I did, just to power. in the first case it will be married to the car without asking for a code, in the latter case it will start prompting for the code after a while. if yo haven't installed it yet, keep playing with just 12V+ and GND connected. if you already installed it, try to connect it in another car or just to power. You should see the prompt eventually...