As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE CREW REPORTED RECEIVING A LAVATORY SMOKE WARNING DURING CLIMB. RETURNED TO DEPARTURE AND LANDED WITHOUT INCIDENT. MAINTENANCE INSPECTED THE ACFT, PERFORMED ENGINE RUNS AND VERIFIED NORMAL OPERATION OF LAVATORY SMOKE DETECTOR WITH NO DEFECTS NOTED, AND THE ACFT WAS APPROVED FOR RETURN TO SERVICE.