After five months of mucking around, I finally managed to get Android Auto on my HTC U11 working with my new 2016 model Honda Civic’s built in stereo system.

First though, the symptoms:

• Neither my HTC M10 nor HTC U11 worked with the Civic’s Android Auto based stereo system
• The HTC phones can however do normal bluetooth based phone calls and play music
• The HTC phones work with Android Auto in other vehicles not made by Honda
• Several different Samsung phones (Note 3, S8 etc) successfully work with Android Auto in the Civic

Things I’d tried unsuccessfully to get Android Auto working:

• Reinstall Android Auto on the phone
• Disable Boost+ power optimisation of the Android Auto application
• Disable Boost+ power optimisation of the Google Maps application

And the trick that got it working in the end?

• Enable USB Debug Mode under the hidden Developer Options menu!

I currently have no idea why this solves the problem, but at least it works…