As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AIRCRAFT RETURNED FROM FLIGHT WITH DOUBLE PRESSURIZATION FAILURE. MAINTENANCE ACTION INVOLVED REPLACING #1 AND OUTFLOW VALVE ACTUATOR (P/N 20219741) AND #1 AND #2 OUTFLOW VALVE MOTOR (P/N 20220141). ALSO #2 PRESSURE CONTROLLER RPLACED. PRESSURIZATION SYSTEM CHECKED SERVICEABLE.