As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FWD AND CONT CAB TEMPERATURE CONTROL IS EXTREMELY ERRATIC AND VERY DIFFICULT TO CONTROL FOR ENTIRE FLIGHT. GROUNDED - YES. FOUND CONTROL CABIN SENSOR DIRTY & SENSOR FILTER & CABIN SENSOR, CLEANED FILTER & REMOVED SENSOR BUILD UP FOR DUST, BOTH RH & LR PZTC BITE NO FAULT, CONTROL TEMP & FWD CABIN TEMP NORMAL FIM 21-61 TASK 861.