Hi, I am new to the forum; however, the dealership has been no help whatsoever. Also, I have an A4, but you guys at this forum seem to be much more helpful than anywhere else.
It is a 2018 A4, and the "Audi Smartphone" option has disappeared from my menu; therefore CarPlay no longer works.
I have attached some screenshots that might help someone help me.
Do you have the Audi smartphone app installed when you plug in? If not you might need to install/reinstall for it to also auto instigate car play. (Im not an iOS user though so only a suggestion)