Google itself acknowledged this problem and already released a fix as part of Android Auto 5.7, claiming that everything was supposed to work correctly. It didn’t, so the company took another shot at bringing things back to normal with Android Auto 6.0, which included additional refinements in this regard.
But as it turns out, not even this new release addresses the notification problem, with some users on Google forums still complaining that Android Auto doesn’t detect new messages, nor does it allow them to turn to Google Assistant to read the content.
“I started having issues with this in the last month or so. I thought it was my cord as i was having issues with the maps also. Changed the cord still have the text problem. I have a Samsung Galaxy S9 hooked up to a Chevy Equinox. I get FB message notifications but never any text messages. I've checked and rechecked all my settings and I've uninstalled and reinstalled AA to my phone twice. Really frustrating,” someone explained earlier this week.
At this point, however, very little is known about whether Google is still monitoring reports or not. On the other hand, there’s nothing else you can try to restore the broken notifications on Android Auto.
Some users claim that downgrading to an earlier version of Android Auto sometimes does the trick, but of course, that doesn’t seem to be anything else than a temporary workaround.
Google is projected to release a new Android Auto update in the coming weeks, so it remains to be seen if that will include additional fixes or not.