As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ORD FLT 5980 THE CREW REPORTED A LAV SMOKE WARNING ON THE EICAS DURING CLIMB. THE AIRCRAFT RETURNED TO ORD AND LANDED WITHOUT INCIDENT. MAINTENANCE INSPECTED AND PERFORMED LAV SMOKE OPERATIONAL CHECKS. COULD NOT DUPLICATE PROBLEM AND NO SMOKE WAS NOTED.