26APR2015
I am posting a bit of a lengthy partial solution here, hoping that a detailed description with many keywords, might be found when searched for by other people with similar issues. I am pretty good with technology, programming with MS Access database, etc., so I consider myself an advanced computer and technology user. I have my smartphone set up more like a laptop and can get more productivity out of it with regards to spreadsheet and presentation manipulation than most can get out of a desktop system, my point being that though a competent techie, I have not come to a permanent fix....yet...if I do, I will post a follow up here.
There seem to be many articles on the Internet discussing inter-connectivity via Bluetooth between the Toyota radio head audio system and various Android Samsung Galaxy phones such as the Galaxy S3, Galaxy S4, Galaxy S5 and Galaxy S6 with regards to having problems with respect to not playing music files (MP3, WMA) stored on the phone via the automatic Bluetooth connection.
I am having a similar problem with the 2015 Toyota Corolla S Plus (owned for about two weeks) with the Entune Premium audio system. The radio head suddenly began having problems not automatically playing music files (MP3 and WMA) via Bluetooth from my Samsung Galaxy S3 Android Smartphone running Android 4.3.3 operating system (NOT rooted). For about a week, when selecting the Bluetooth audio mode on the car's audio system, the car's audio system worked fine, automatically playing the music files stored on my phone, displaying the Artist, Track Title and Album names as well as the Cover Art on the radio head display.
I will explain my temporary fix first, then the steps I had tried which did not work. Regardless, I have called Toyota Corporation, though the guy was pleasant, he had not run into this problem and could not assist, thus, I will be taking the car to my Toyota dealer this week.
*******HERE IS THE TEMPORARY FIX I CAME UP WITH. **********
(I use WinAmp as my music player on the phone, but this will work with the default Samsung Music or Google Play music file (MP3, WMA) player APPs.
From the Google Play Store, I downloaded the SoundAbout (one word) APP. Basically, this APP has settings which force audio from the phone to be routed to a Bluetooth device such as an earpiece, the car (A2DP protocol) as well as allowing the user to select other protocols based on the device designated to receive the audio. Having first paired the phone to the car once, I then subsequently start the car, wait for the audio system to boot up and select the Bluetooth audio mode. Next, I turn on my phone's BlueTooth, launch the WinAmp player (or music player of your choice) on the phone, select a song to play, then PLAY (Random and other play modes must be set once). This causes the SoundAbout APP to send the audio via Bluetooth to the radio head and the music plays through the car stereo (and the calls also go through the radio head, when a call is complete, WinAMP continues playing music automatically). I can even change tracks by using the thumb pad of the steering wheel. There are only two issues with this arrangement, first, the audio track titles/information and Cover Art are not displayed on the car's radio head display, and secondly, the car radio head is simply not working as it should, it is much cooler to show your family and friends how the car automatically plays music files from the phone via Bluetooth without touching the phone for true, safe, hands free operation...thus the reason I will take the car to the Toyota dealer this week.
****the settings used on the SoundAbout APP, after experimentation, which work for me are: SoundAbout SERVICE-On With Status; Media Audio-Let APP Decide; Phone Call Audio-Let APP Decide; Connectible Devices/Bluetooth Settings-Bluetooth Auto Enable CHECKED.
****Steps I had taken found from various websites which DID NOT SOLVE my issues, in order from advanced to rudimentary:**********
-It was suggested to ROOT the phone....HECK NO, to many APPS and too much data to re-install!
-Cleared the Bluetooth cache and data under the Phone's SETTINGS/MORE/APPLICATION MANAGER (at this point scroll to the right to get to ALL)/Bluetooth SHARE (select by tapping once), select FORCE STOP, CLEAR CACHE, CLEAR DATA...then reboot the phone.
-There was another option which did not work regarding clearing the music cache on the phone, I do not recall the steps right now, but they can be searched for on the internet, but it did not work.
-Delete the phone from the Toyota radio head audio system, turn the car off, unpair the Toyota Bluetooth connection from the phone, reboot the phone. Start the car and re-pair the phone to the car. (hint, not sure why anyone bothers suggesting this as a fix online. If you as the user have not figured out on your own to "re-boot" the system from scratch and try again, you should probably not have purchased such a car audio system, and none of us would be looking for such a simple solution on the internet, thus such postings are inconceivable to me, all they do is become the top listed solutions, which of course do not work in most cases).