As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CABIN TEMP REFERENCE IS BLANK ZONE B. REPLACED TRIM VALVE PER MM, OP CHECKED GOOD. CHECKED ALL WIRES FROM CTC TO ZONE 'B' TRIM AIR MODULATING VALVE, CHECKED GOOD. SWAPPED VALVE WITH KNOWN GOOD VALVE, CHECKED GOOD. CONFIRMED BAD VALVE. RESET CTC AND OPERATED CONTROL PANEL. ALL TEMPS AND CTL CHECKS GOOD. FOUND TEMPS AND CTL FOR ALL ZONES AT 1L CSCP PANEL WORKING.