Bluetooth Connection-'11 Hyundai Sonota


My problem is that I sucessfully auto connect through my car's bluetooth less than 50% of the time. My HTC Hero's bluetooth is enabled and the phone is paired to the vehicle. The only way I can make the connection is to go to the phones settings, wireless controls then shut off bluetooth, then recheck it so I can see and check the discoverable option. Can anyone advise how I can solve this VERY annoying proble?? Much appreciated.