As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
HAD ZONE TEMP ON RECALL ENROUTE RAN QRH AND IT WENT OUT. GROUNDED - YES. PERFORMED PACK TEMP CONTROL BITE PROCEDURE PER B737-900 FIM 21-62 TASK 801. HAD FAULT FLT DECK TRIM VALVE ON PREVIOUS FLIGHT. PERFORMED FIM 21-62 TASK 832 AND DURING INITIAL EVALUATION FAULT CLEARED AND NO FURTHER ACTION NECESSARY.