What was found
ON FLIGHT 3307 THE CREW REPORTED, DETECTED A BURNING SMELL ON THE TAKEOFF AND CLIMB AND THEN RECEIVED A BLEED 2 VALVE FAIL MESSAGE THAT WENT TO X-BLEED AND THEN THE ODOR WENT AWAY. THE CREW ELECTED TO RETURN TO DFW. THE AIRCRAFT LANDED WITHOUT INCIDENT. THE AIRCRAFT WAS REMOVED FROM SERVICE. REMOVED AND REPLACED THE NUMBER 2 PRECOOLER OUTLET TEMPERATURE SENSOR IAW EMB140 AMM 36-20-01. THE OPERATIONAL CHECK WAS GOOD IAW EMB140 AMM 36-00-00. THE ENGINE RUNS CAME UP CLEAN OF ANY ODORS. THE AIRCRAFT WAS RETURNED TO SERVICE.