The issue I have is similar to yours, audio is not playing back on my car but in other cars it does work. did you find a workaround? Or a root cause? can you test if what I described on my issue below works for you, you try to play audio then quickly move to a Music app and play music, in my case I hear the audio from my app also playing together then. https://developer.apple.com/forums/thread/823974

Update: I was granted the voice conversation entitlement and added to my app together with the driving task entitlement. it didn’t improve the audio playback, it doesn’t play audio reliably yet, the weird thing is that on my test device (a cheap CarPlay screen bought on Amazon) it plays correctly but not on my car (Nio firefly 2025-2026), but in my car other apps such as ChatGPT play record and play audio normally so I am really lost in here.