Nokia X3-01 Bluetooth Repair Solution
You may start checking the Bluetooth module chip supply voltages in two capacitors. These voltages range 2.6V and the other one is 3.8 volts.
If the voltage readings is okay, check the UART resistors then replace if found damaged or faulty.
The next step is to reheat, rework or replace the Bluetoot IC if the above steps is already been done and if the problem still exists.
If seems the above procedures does not solved the problem the next option is to replace the Bluetooth crystal oscillator.