As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AUTO FUNCTION FAILED ON CABIN CONTROLLER. CAUSING PRESSURIZATION LOSS. PILOT SWITCHED TO MANUAL, REPORTED ERRATIC CONTROL OF CABIN IN MANUAL MODE. IN AUTO MODE TROUBLESHOOTING, FOUND CONTROLLER FAILING THE BUILT IN TEST IAW AMM 21-30-00. PRIMARY OUTFLOW FALVE WAS LEAKING ON AT THE MANUAL CHAMBER CAUSING ERRATIC MANUAL MODE CABIN CONTROL.