As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CONT CAB ZONE TEMP LIGHT ILLUMINATES ON MASTER CAUTION RECALL. GROUNDED - YES. #2 PZTC SHOWS FLT DECK TRIM VALVE FAULT. ACCOMPLISHED PZTC BITE TEST REF B737-800 AMM 21-61-00-700-806-002. FAULT RESET. PERFORMED CABIN ZONE TEMP CONTROL AND INDICATION OPERATIONAL TEST REF AMM 21-61-00-700-807-002. OPS CK GOOD.