Though my current car doesn't have Android Auto, I'm renting a car with it. This is my first experience with it and it's kind of cool. I'm wondering what degree (if any) I'll be able to use Cortana with it now and in the future. I'll fiddle with it over the next couple of days, too.
@msloganjr With my Windows phone I never needed an extra app on my device OR my car. I have a 2013 Camaro with MyLink. All I had to do was pair my phone with the Bluetooth on my car and I could simply press the "call" button on my steering wheel and say, "Call Cortana". The system would "call" Cortana and I could immediately send texts, play music, etc. I NEED to be able to do that with the Android device. Cortana is 100% non-functional with my car. It's impossible to access Cortana via Bluetooth.
Don't get your hopes up. Android doesn't give Cortana very deep access to the phone and the operating system of the phone is what drives Android Auto.
Sad thing, as mentioned above, 5 (FIVE) years ago, with my Windows Phone mounted on my dash, all I had to do was say "Hey Cortana" and from there I could make calls, send texts, have them read to me and respond. That you cannot do that with Android - today - it fodder for a class action lawsuit - of Google and the NHTSA.