What was found
AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED AND THE AIRCRAFT DIVERTED TO LAS DUE TO YELLOW HYDRAULIC SYSTEM ENGINE 2 PUMP LOW PRESSURE ECAM MESSAGE. THE AIRCRAFT LANDED SAFELY AT LAS WHERE THE AIRCRAFT WAS ABLE TO EXIT THE RUNWAY UNDER ITS OWN POWER. AFTER EXITING THE RUNWAY THE AIRCRAFT WAS TOWED TO THE GATE, MAINTENANCE REPLACED YELLOW HYDRAULIC SYSTEM HIGH PRESSURE MANIFOLD UNION O-RING PER AMM 29-13-14 AND ACCOMPLISHED A SATISFACTORY LEAK / OPERATIONAL CHECK.