As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED SMOKE TOILET CAS MESSAGE CAME ON DURING DESCENT. PASSENGER NEAR LAV REPORTED ELECTRIC BURNING SMELL. CREW RAN QRH (QUICK REFERENCE HANDBOOK) AND LANDED SAFELY. MAINTENANCE INSPECTED LAV AND CABIN AREA, GROUND RAN AIRCRAFT WITH CREW AND RAN AIR CONDITIONING SYSTEM. NO DEFECTS AND NO INDICATIONS OR EVIDENCE OF LAV SMOKE NOTED. MAINTENANCE REMOVED AND REPLACED RIGHT ENGINE NUMBER ONE CARBON SEAL DUE TO EVIDENCE OF LEAKING OIL AND PERFORMED CHECKS USING AIRCRAFT MAINTENANCE MANUALS. AIRCRAFT RELEASED FOR SERVICE.