What was found
AN EMERGENCY WAS DECLARED DUE TO: DURING CLIMBOUT AIR CONDITION MASTER CAUTION WITH PRESSURIZATION PANEL AUTO FAIL ILLUMINATED; AIRCRAFT FAILED TO PRESSURIZE, CABIN ALTITUDE WAS CLIMBING WITH AIRCRAFT AND DIFFERENTIAL PRESSURE REMAINED ZERO, WAS ABLE TO USE MANUAL MODE TO CONTROL OUTFLOW VALVE. AIRCRAFT AIR INTERRUPTED BACK TO AND LANDED SAFELY AT PHX. FOUND CPC NUMBER 2 INOPERATIVE. REMOVE AND REPLACED BOTH CPC NUMBER 1 (AALA202503177539) AND CPC NUMBER 2 (AALA202503202283). PER AMM 21-31-01. SYSTEM GROUND TEST CHECK GOOD**(CLOSED).