As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LGA - FLT 4401 - AFTER TAKEOFF, CREW REPORTED LAVATORY SMOKE MESSAGE ON EICAS AND SMOKE IN CABIN. APU ALREADY ON MEL. MAINTENANCE REMOVED AND REPLACED THE LEFT ENGINE IAW EMB MM. OPERATIONAL AND LEAK CHECKS WERE SATISFACTORY AND AIRCRAFT WAS RETURNED TO SERVICE. (M)