I’m not sure if this bug is specific to my make and model of car but I’ve finally found a way to fix this annoying bug. I have a Volkswagen Golf GTE with factory fitted CarPlay and about 50% of the time it would not play any audio. I would turn the volume up and it would say ‘No Audio’.
I’ve found a fix, well a hack really. If you move into the Media section first then do a new Bluetooth search for your iPhone. Once you have seen the iPhone in the list of discoverable devices don’t tap it. Simply tap app again to go into CarPlay, the audio will magically start working again.