As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MCI FLIGHT 2248 THE CREW REPORTED A LAV SMOKE WARNING ON TAKEOFF. THE AIRCRAFT RETURNED AND LANDED WITHOUT FURTHER INCIDENT. NO SMOKE WAS NOTED. MAINTENANCE INSPECTED THE SMOKE DETECTION SYSTEM AND NO DEFECTS WERE FOUND. THE AIRCRAFT WAS RELEASED FOR SERVICE.