As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON FLIGHT 4870, CREW REPORTED LAV SMOKE ON EICAS IMMEDIATELY AFTER TAKEOFF, NO SMOKE FOUND BY FA, STAYED ON FOR APPROX 5 MINS AND WHEN OFF. RETURN TO CMH. REMOVED AND REPLACED NUMBER TWO. REMOVED AND REPLACED THE TEFLON LIP SEAL AND THE NR 4 CARBON SEAL. OPERATIONAL CHECKS WERE GOOD. THE AIRCRAFT WAS RETURNED TO SERVICE.