As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED HEARING LAVATORY SMOKE DETECTOR ALARM FOLLOWED BY MESSAGE IN THE COCKPIT AT 3000 FT. THE CREW FOLLOWED QRH, DECLARED AN EMERGENCY, RETURNED TO FIELD AND LANDED WITHOUT INCIDENT. MAINTENANCE TROUBLESHOT, R & R THE LAVATORY SMOKE DETECTOR AND PERFORMED CHECKS IAW THE AMM. ACFT RELEASED FOR SERVICE.