so the radio doesnt support stereo Bluetooth that’s why you cant bluetooth audio to your stereo form your iphone but... you can bluetooth phone calls to your stereo because its a different bluetooth profile which is a mono signal only the front left and right speakers
so if you dont care about sound quality and want to bluetooth audio from your iphone to radio example pandora, ipod, any apps, sms phone and email alerts, follow these steps
keep in mind audio quality sucks.....
go to cydia search for Bluetooth
you should see something named Bluetooth mono sbsettings click it install