As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE FLIGHT CREW REPORTED THAT DURING FLIGHT RECEIVING AN AMBER "BLEED AIR OVERTEMP - L" ADVISORY. THE CREW ATTEMPTED ONE RESET OF SYSTEM, BUT THE MESSAGE RE-APPEARED. THE CREW TURNED THE LH BLEED AIR SYSTEM OFF PER CHECKLIST THE REMAINDER OF THE FLIGHT. THE MAINTENANCE TEAM GAINED ACCESS TO THE LH ENGINE PYLON AREA, TROUBLESHOT THE SYSTEM AND DETERMINED THE LH PRECOOLER TEMP CONTROL SENSOR WAS DEFECTIVE. A NEW SENSOR WAS INSTALLED AND FUNCTIONAL CHECKS WERE SATISFACTORY. THE AIRCRAFT WAS THEN RETURNED TO SERVICE.