As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTS, UNABLE TO PRESSURIZE AIRPLANE AFTER TAKEOFF. CAN CONTROL OUTFLOW VALVE OPEN AND CLOSE. THE RIGHT FLOW CONTROL VALVE WOULD NOT TURN ON. REPLACED FLOW CONTROL VALVE AND CONNECTOR PINS. THE SHOP FOUND THE FLOW CONTROL VALVE HAD LOW AIR FLOW CAUSED BY A FAILED BUTTERFLY SEAL, A SENSE LINE WITH A HOLE IN IT, A BAD FILTER CIRCUIT AND FROZEN MOTOR BEARINGS.