Android Auto is not worrying correctly with my Pixel 2 XL, I have a Kenwood DDX9903S in my car on the latest firmware. I have previously used the original Pixel XL and a Samsung S8+ on it with no issues.
What it is doing is this: I plug it into the regular USB port that I did with the others, this is a Kenwood cable that plugs into the radio, it has two USB plugs on it, one for Android/iPhone, one for a USB drive. I'm using a USB A to C cable purchased from the Google Store to connect. When I plug it in the radio doesn't detect the phone at all, it only charges my phone. I went into developer settings and turned on USB Debugging, this caused it to work part of the time, the radio will detect the phone and launch Android Auto. This doesn't always work, sometimes it locks up, others it just stops and says it has a "USB Access Error." It has now started saying unsupported device here and there.
It's been very frustrating since I drive 40 minutes to work each way and used Android Auto for podcasts and audiobooks daily.