As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE FLIGHT, NR 2 ENG FIRE WARNING LIGHT & TONE CAME ON FOR 2 SECONDS & WENT OUT WITH NO OTHER INDICATIONS. ACFT SLOWED TO SINGLE ENG AIRSPEED & PROCEEDED TO NEAREST AIRPORT. CLEANED FLAME DETECTORS & PERFORMED FIRE DETECTION SYS CHECK, COULD NOT DUPLICATE.