As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ISOLATION VALVE STAYS CLOSED WHEN SWITCH ON P5-10 PANEL SELECTED TO AUTO. ACFT GROUNDED. REPLACED AIR CONDITIONING MODULE (P5-10 PANEL) IAW MM 21-51-65. INSTALLATION TEST GOOD IAW SAME. PACK ZONE TEMP CONT BITE TESTS GOOD. REF MM 21-51-00. RECIRCULATION SYS OPS TEST GOOD IAW MM 21-25-00.