A number of users using Google Maps in Android Auto mode report the Searching for GPS error message appearing, disabling the navigation function.
In the absence of an official explanation from the Google Maps team, the temporary solution may be to set your phone so that the screen stays on for the duration of the Android Auto session. But for users who use wireless connectivity instead of a USB cable, the proposed fix comes with the drawback of quickly draining the battery.
Another possible solution is to manually tick the permissions granted on the phone to the Google Maps app, changing the “only while using app” option to “allow all the time”. Another suggestion would be to uncheck “Optimized battery usage”. And with these “fixes” battery consumption could increase, especially during periods when you’re not actually using Google Maps, but the app is left open in the background.
Alternatively, those who run into this problem could switch to the Waze alternative, also available in an Android Auto version.
Apparently, the problem reported just a few weeks ago could be the consequence of a less-than-successful update delivered by Google, with unlucky ones who run into this bug turning to the Google Support forum to request a fix.