As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFT CABIN ZONE TEMP ILLUMINATES ON RECALL. ACFT GROUNDED. PERFORMED PACK - ZONE TEMPERATURE CONTROLLER BITE TEST IAW AMM 21-61-00/501. LEFT PACK - ZONE TEMP CONTROLLER SHOWED ZONE TRIM VALVE FAULT FOR PREVIOUS FLIGHT. FOUND AFT ZONE TEMP FILTER AND SENSOR EXTREMELY DIRTY. REPLACED AFT ZONE TEMP SENSOR FILTER AND CLEANED SENSOR IAW AMM 21-61-06/201, AND AMM 21-61-10. OPS NORMAL.