Default Samsung Galaxy S3 i9305 Bluetooth Headset

Hi all!
On my S3 LTE Device I have the latest 4.4.3-20140615-i9305-NIGHTLY installed. Its working very well with one exception: The Bluetooth Headset connection with my car stereo is not functional. Its paired and seems to work, but there is no audio function in both direction.

Earlier, with the stock rom it worked, later with cyanogenmod nightly I had the same problem.