As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
JFK - INFLIGHT MIA-LGA. THE CENTER HYDRAULIC SYSTEM INDICATION TRANSMITTER FAULTY. EMERGENCY DECLARED, LANDED JFK WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. REPLACED HYDRAULIC QUANTITY MONITOR UNIT. SYSTEM GROUND CHECK NORMAL OPERATION.