As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CVG TO IND - DURING TAKEOFF A "LAV SMOKE" EICAS MESSAGE WAS DISPLAYED AT APPROXIMATELY 1500 FEET. THE FLIGHT CREW PREPARED TO RETURN TO FIELD AND PERFORMED THE APPLICABLE QRH CHECK LISTS. THE FLIGHT ATTENDANT REPORTED THAT THERE WAS NO VISIBLE SMOKE OR ODOR COMING FROM THE LAVATORY. THE AIRCRAFT LANDED WITHOUT INCIDENT AND WAS TURNED OVER TO MAINTENANCE. MAINTENANCE REMOVED AND REPLACED THE LAVATORY SMOKE DETECTOR, RAN BOTH ENGINES AND COULD NOT DUPLICATE THE FAULT.