As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRPLANE WAS NOT ABLE TO PRESSURIZE IN AUTO MODE. CABIN CLIMB GAGE WAS ERRATIC. OK ON MANUAL MODE. PERFORMED FIM 36-10 TASK 810. FOUND #2 ENGINE HIGH STAGE REGULATOR REGULATES CONTROL PRESSURE TOO LOW. REMOVED AND REPLACED #2 ENG. HIGH STAGE REGULATOR IAW AMM 36-11-07. OP'S CHECK GOOD. ENGINE SUPPLY PRESSURE WITHIN NORMAL OPERATION LIMITS AT IDLE.