As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT HAD A LAVATORY SMOKE CAUTION MESSAGE IN FLIGHT. FLIGHT CREW DECLARED AN EMERGENCY AND AN OTHERWISE UNEVENTFUL LANDING WAS MADE. MAINTENANCE PERFORMED A SUCCESSFUL OPERATIONAL CHECK OF THE SMOKE DETECTION SYSTEM IAW APPROVED AMM PROCEDURES.