As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF, CREW REPORTED A LAVATORY SMOKE INDICATION. RAN QRH ITEMS AND MESSAGE WENT AWAY, NO SMOKE NOTED. ACFT LANDED WITHOUT INCIDENT. MX R & R LAVATORY SMOKE DETECTOR, OPS TESTED WITH NO DEFECTS, AND ACFT APPROVED FOR RETURN TO SERVICE.