As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF, LEFT DUCT OVER-TEMP LIGHT CAME ON. THE AIRCRAFT RETURNED TO FIELD. THROUGH TROUBLESHOOTING, DETERMINED LEFT DUAL TEMP CONTROL VALVE WAS THE PROBLEM. THE VALVE WAS REPLACED AND A FUNCTIONAL CHECK OF THE SYSTEM PERFORMED WITH ALL INDICATIONS NORMAL.