I have a VW Golf with Bluetooth enabled Radio, and a Parrot kit before that.
I have had a Galaxy S3 and then a HTC One M8 and now a Galaxy S6.
On the S3/HTC One M8 in both my cars, whenever I got in the phone would auto-play as soon as Bluetooth connected whatever I had last used to play media. (Either Google Music or TuneIn)
This does not seem to work very well with the Galaxy S6. It seems only 1 in 10 times that I get in the car will the phone auto-play my music. I have to manually start google music for it to work.
The strange thing is the car displays the song and artist on the head unit but when I press play, it just wont work. I need to press play on the phone.
I mentioned my other phones and car kits as I really want to steer clear of the issue being the car's stereo.
It worked fine with other phones and has not been updated or changed since.
I can also so the car trying to instruct the phone to play, but not succeeding.
Please help! Its defeating the nice feature of BT streaming Audio. Love just keeping my phone in my pocket and getting in the car and it auto-playing.