P30 Pro keeps rebooting when connected to Android Auto

[Android Central Question]

I've got an aftermarket Eonon stereo in my car and have been using a cabled connection to my P30 Pro since the summer. Worked fine last night, but this morning I plugged in and the phone rebooted. Got to login screen, I entered my password and it rebooted again. I removed the password setting, connected my phone and it rebooted. Now whenever I plug my phone into the stereo, it forces are reboot and I can't get to the bottom of it - has anyone got any ideas?