As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON FLIGHT 3989, CREW REPORTED LAV SMOKE WARNING ON EICAS AFTER TAKEOFF. FLIGHT ATTENDANT DID NOT HAVE ANY INDICATIONS OF SMOKE. AIRCRAFT REMOVED FOR SERVICE. REMOVED AND REPLACED LAV SMOKE DETECTOR IAW EMB 135 AMM 26-14-01. OPERATION CHECK GOOD. AIRCRAFT RETURNED TO SERVICE.