As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF THE CREW RECEIVED A LAV SMOKE INDICATION ON EICAS WHILE CLIMBING THROUGH 1,000FT. THE AIRCRAFT RETURNED TO LGA AND LANDED WITHOUT INCIDENT. THE AIRCRAFT WAS THEN FERRIED TO CMH FOR FURTHER TROUBLESHOOTING. CMH MAINTENANCE RAN THE ENGINES AND PACKS IN MULTIPLE CONFIGURATIONS AND COULD NOT RE-CREATE THE FAULT AND NO FAULTS WERE FOUND WHILE USING THE AERO TRACER. THE LAVATORY SMOKE DETECTOR AND TEST PANEL WERE REPLACED AND THE SUBSEQUENT TEST FLIGHT FOUND NO FURTHER DEFECTS.