Android Auto doesn't work with Z5C and VW head unit

[7-Zark-7]

I can't get my Z5 Compact run Android Auto when connected to my VW Discovery Navigate unit.  Every time I try, the connection process fails and the connection fails over to Mirrorlink instead.

I suspect that the problem is related to the fact that the phone always defaults to 'USB Charging' mode and not MTP when the initial connection is tried.  By the time I can manually change over to MTP on the handset, the connection has failed.  The selection of MTP for USB mode never seems to 'hold' as every time I try to re-initiate the connection (with the phone still plugged in from the last time) it resets to 'USB charging'.

Phone is on Marshmallow, 6.0 - Build number 32.1.A.1.163

[MarlonUk1]

are you connecting the phone via USB? because those options ( mtp, charging only, midi) are only for usb connections. did you check with the VW Discovery Navigate manufacturers regarding about support and compatibility?

[7-Zark-7]

Managed to get it working in the end using a different USB cable ...  for some reason, the head unit sems to be sensitive to the USB cable used.

But you do need to manually set MTP mode whenever the phone is physically connected and it doesn't remain as default, which is a bit of a pain.  I appreciate that 'USB charge mode' is for security in the event that people plug into unknown public USB charge sources but there should be a way to make MTP the default for those who know what they are doing.