As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CONT CAB ZONE TEMP CAUTION, DID QRH, WENT AWAY, COMES ON RECALL ONLY NOW. GROUNDED - YES. RESET CONT CABIN TRIM VALVE FAULT. OBSERVED TAV DURING PZTC BITE. NO ABNORMALITIES NOTED. OP CK NORMAL SEVERAL TIMES. REF B737-800 FIM 21-62 TASK 832.