As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
JFK - INFLIGHT ORD-LHR. CREW REPORTED LEFT HYDRAULIC SYSTEM QUANTITY STATUS MESSAGE. EMERGENCY DECLARED FLIGHT DIVERTED JFK LANDED WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. FOUND LEFT HYDRAULIC DIFFERENTIAL PRESSURE INDICATOR LEAKING ON LEFT PYLON CASE DRAIN FILTER MODULE. REPLACED HYDRAULIC DIFFERENTIAL PRESSURE INDICATOR. SYSTEM GROUND CHECK NORMAL OPERATION.