As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEVEL AT FL430, HAD A DUCT 1 OVERTEMP CASS MESSAGE. RAN THE QRH & COULD NOT GET IT TO GO AWAY UNTIL PULLED THE THROTTLE TO IDLE. DIVERTED AND LANDED WITH THE NR 1 THROTTLE AT IDLE. REMOVED COCKPIT TEMPERATURE MODULATING VALVE AND INSTALLED OVERHAULED COCKPIT TEMPERATURE MODULATING VALVE IAW AMM 21-61-02. OP CHECKED GOOD, NO FAULTS. REMOVED DUCT TEMPERATURE SENSOR AND INSTALLED NEW DUCT TEMPERATURE SENSOR IAW 21-61-03-000-801-A AND 21-61-03-400-801 OP CHECKED GOOD, NO FAULTS.