As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ENGINE INDICATING CREW ALERTING SYSTEM (EICAS) MESSAGE "FIRE MN DK MID". - BENT PIN DISCOVERED ON LOOP B RELAY R5168 CAUSING INTERMITTANT LOOP B FIRE WARNING INDICATION. REPLACED RELAY R5168. LOOP B FUNCTIONS NORMAL PER AIRCRAFT MAINTENANCE MANUAL 26-10-00. DEFERRED MAIN DECK CARGO FIRE WARNING LOOP A SYSTEM PER MEL 26-14-01-02.