As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
JFK T003/27DEC03 EN ROUTE JFK-LAX AFTER TAKEOFF, LANDING GEAR MONITOR MESSAGE WITH AURAL WARNING. UNABLE TO SILENCE. AIRCRAFT RETURNED JFK LANDING WITHOUT INCIDENT. REPLACED GROUND PROXIMITY ELECTRONIC UNIT. SYSTEM GROUND CHECKED OPERATION NORMAL.