Bluetooth audio does not work in car radio, did before

Bug Reports
3

One thing to try is:

  1. Remove the phone from the car system
  2. Remove the car from the phone.
  3. Pair the devices again.

It is better to start from the current release than to jump five releases like you did, alot has changed from 4.0.1.48 to 4.5.0.19.

You can follow the guide Installing Sailfish X again to Xperia