As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: 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. (OPEN).