Hi roseann235,
I see there has been no further development on this topic for a month. I was looking, again, for any progress, though it seems Apple and other developers are not interested.
I have some info that may ease the pain for others that are experiencing this issue: I’ve been experiencing the same issue since updating to iOS 16 last year. The ‘work around’ I’ve had to do every time this happens is; once connected to Car Play (mine is USB), unlock the iPhone and bring up Google Maps, or other affected app, so the iPhone has the app in the foreground. If you already have the app open on Car Play you should see it come to life and begin working on your in-car display.
I can then lock my iPhone and Car Play will work as expected; switch between apps, close and re-open Google Maps etc. It seems iOS 16 won’t let Car Play access any 3rd party apps in the ‘background’ after the iPhone is locked.
This routine repeats EVERY time I unplug / replug the iPhone in the car. Very frustrating.
On iOS 15 this issue was also present until you changed the settings in the iPhone: ‘Background App Refresh’ - Google maps turned on, and ‘Allow Notifications - Lock Screen’, and of course ‘Privacy & Security - Location Services - Google Maps set to Always’. These were all necessary to allow Car Play to extend these apps onto the in-car display. However it did work properly once you changed these settings, unlike iOS 16.