As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON FLIGHT 4078, CREW REPORTED AFTER TAKEOFF RECEIVED LAV SMOKE WARNING. F/A REPORTS NO VISUAL SMOKE OR ODOR. AIRCRAFT RETURNED TO FIELD WITHOUT FURTHER INCIDENT. AIRCRAFT REMOVED FROM SERVICE. FOUND 0 CARBON SEAL LEAKING REMOVED AND REPLACED "0" CARBON SEAL OPERATIONAL CHECK GOOD. AIRCRAFT RETURNED TO SERVICE.