What was found
DURING CLIMB, NOTICED AIRCRAFT NOT PRESSURIZING IN AUTO MODE, THE AIRCRAFT DID PRESSURIZE IN MANUAL MODE. REMOVED FROM SERVICE. INTERROGATED CDS AND FOUND CPC/OF VALVE DATA FAILED AND CP CONTROLLER FAILED FAULTS. UNABLE TO CLEAR FAULTS. REMOVED AND REPLACED THE CABIN PRESSURE CONTROLLER IAW AMM 21-31-06-000-801, AND 21-31-06-400-801. FAULTS NOW CLEAR. OPS TESTED GOOD. ALSO PERFORMED FUNCTIONAL TEST OF THE PRESSURIZATION CONTROL USING APU AIR IAW AMM 21-31-00720-801, FUNCTIONAL TEST GOOD. AIRCRAFT RETURNED TO SERVICE.