Users who turned to this Google forums thread explain that this weird behavior started happening all of a sudden following a recent Android Auto update.
“I noticed that it simply won’t cast anymore and the vehicle doesn’t seem to acknowledge that my phone is connected via USB at all,” one user explains.
Replacing the cables, clearing the cache and data of Android Auto and the other apps, removing and re-installing everything are all workarounds that made no difference.
“I decided to do some troubleshooting and I noticed that when I connect my phone, it will start up android auto (as seen from the notification panel) and then quickly go away. The thing that makes this even more interesting is that when I go USB settings and change the ‘use USB for’ section to ‘transferring files / Android Auto’ it will change appropriately for a second and then it will then change to charging phone only regardless of how many times I try to force the phone to change,” the original poster says.
Several others have confirmed the same problem in the car, but what’s worse is that car manufacturers and phone makers both have a hard time figuring out what’s happening.
Someone says they took their Ford to the dealership only to find out that other mobile devices work correctly and run Android Auto properly. When reaching out to Samsung, however, the company sent a replacement Galaxy S10+ that was also unable to launch the app on the head unit. Samsung eventually inspected the phone with no result, one customer says.
At this point, no workaround is known to exist, and Google has so far remained tight-lipped on everything.