As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED AND THE AIRCRAFT RETURNED TO DFW DUE TO THE FLIGHT CREW REPORTING AN YELLOW HYDRAULIC RESERVOIR LOW LEVEL ECAM MESSAGE AND THAT THEY LOST ALL YELLOW HYDRAULIC FLUID. THE AIRCRAFT LANDED SAFELY AT DFW WITHOUT FURTHER INCIDENT. MAINTENANCE FOUND THE YELLOW HYDRAULC LINE IN THE PYLON LEAKING, REPLACED LINE AND ACCOMPLISHED A SATISFACTORY LEAK / OPERATIONAL CHECK WITH NO ISSUES NOTED,