As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AFTER TAKEOFF, THE NR 2 HYDRAULIC SYSTEM QUANTITY DROPPED TO 2 QUARTS AND THEY RECEIVED A RUDDER ISO CAUTION LIGHT. THE ACFT RETURNED TO THE DEPARTURE AIRPORT WITHOUT INCIDENT. MAINTENANCE INVESTIGATION FOUND THE RT MLG DOOR SEQUENCE VALVE FAILED WHICH CAUSED THE FLUID LOSS. THE DOOR SEQUENCE VALVE WAS REPLACED AND THE ACFT RETURNED TO SERVICE. DOOR SEQUENCE SOLENOID VALVE, PN 54C54634-7, SN 0129B. ACFT TSN 57483, CSN 71843.