As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 5940. CREW RETURNED TO FIELD FOR A LAV SMOKE INDICATION ON EICAS. MAINT FOUND THE LAVATORY SMOKE DETECTOR FULL OF DUST. AFTER CLEANING THE SMOKE DETECTOR THE SYS WAS OPS CHECKED GOOD. LATER THAT DAY THE MESSAGE RETURNED WHILE ON APPROACH AND CLEARED WITHIN 40 SECONDS. THE CREW PERFORMED A NORMAL APPROACH AND LANDING. MAINT ISOLATED THE FAULT TO E2 WHILE AT HIGH POWER. THE AC WAS THEN FERRIED TO CMH WHERE E2 WAS REPLACED. AFTER REPLACING E2 THERE WERE NO FURTHER FAULTS NOTED.