As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE IN LEVEL FLIGHT, NR 2 ENGINE FIRE LIGHT ILLUMINATED. PERFORMED CLEARING TURN TO CHECK FOR SMOKE. NO SMOKE WAS NOTED. FOLLOWED EMERGENCY CHECKLIST AND RETURNED TO BASE. TROUBLESHOT SYSTEM. FOUND FIRE CONTROL UNIT UNSERVICEABLE. REPLACED FIRE CONTROL UNIT.