What was found
AFTER TAKEOFF FROM PHX EN ROUTE FOR BWI RECEIVED ECAM MESSAGE NR 2 ENGINE BLEED FAULT: TURNED BACK TO PHX FOR REPAIR. MAINTENANCE REMOVED AND REPLACED NR 2 ENGINE FAN AIR VALVE CONTROL THERMOSTAT 7170HM2 IAW AMM 36-11-43-04, ALSO REPLACED DEFECTIVE LINE THAT CONNECTS TO FAN AIR VALVE AND THERMOSTAT 7170HM2, OPERATIONAL CHECK WAS GOOD. VENDOR CONFIRMED FAILURE OF TEMPERATURE CONTROL THERMOSTAT S/N 03205 FINDING THE UNION WAS CROSS THREADED CAUSING AIR TO LEAK AT SENSE LINE. REPLACED DAMAGED UNION IAW CMM 36-11-44, AND COMPLIED WITH SB 342-36-06. UNIT TESTED AND RETURNED TO SERVICE.