As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE RECEIVED "HYD Y RSVR LO LVL" MESSAGE. SHUT DOWN THE YELLOW HYDRAULIC SYSTEM PER COM PROCEDURES AND CONTINUED TO FINAL DESTINATION WITHOUT INCIDENT. MAINTENANCE REPLACED LEAKING O-RING ON LINE BETWEEN PTU MANIFOLD AND PTU. RESERVICED SYSTEM. NO LEAKS NOTED.