As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: AN EMERGENCY WAS DECLARED AND THE AIRCRAFT RETURNED TO MIA DUE TO GREEN HYDRAULIC SYSTEM LOW PRESSURE WARNING POPPING UP AND GOING AWAY SEVERAL TIMES INFLIGHT. THE AIRCRAFT LANDED SAFELY AT MIA WITHOUT FURTHER INCIDENT AND TAXIED TO THE GATE UNDER ITS OWN POWER. MAINTENANCE REPLACED THE GREEN HYDRAULIC SYSTEM PRESSURE SWITCH 1151GN PER AMM 29-32-12 AND ACCOMPLISHED A SATISFACTORY LEAK / OPERATIONAL CHECK.