As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON CRUISE FROM MPR TO SDL CREW RECEIVED “AIR DUCT OVERHEAT ANNUNCIATION” AFTER TWO MINUTES, PASSENGER COMPLAINED OF HIGH TEMPERATURE AND CABIN HAD SMOKE. CREW DECLARED AN EMERGENCY AND DIVERTED TO NEAREST AIRPORT (RTN). ON-SITE MAINTENANCE FOUND DEFECTIVE RAM-AIR MODULATING VALVE. VALVE WAS REPLACED AND OPERATIONAL CHECK WAS SATISFACTORY. AIRCRAFT RETURNED TO SERVICE.