To fix Bluetooh X2-01 problem you may first check the device firmware. and try to restore it, flash or update it. If the device suffered wet damaged, you may first take a check up on the bluetooth components, clean it first, by using a liquid cleaner. Check the antenna connection pads and connector, if the connection is weak it will also result to connection error and malfunction..
Check and trace the supply voltages to the bluetooth module... If the voltages were okay, then you may proceed to re-working and replacement procedure.
Nokia X2-01 Bluetooth Problem Hardware Solution