As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ENGINE FIRE ALARM INTERMITTENTLY SOUNDED FALSE WARNING DURING FLIGHT. PERFORMED TROUBLESHOOTING OF THE SYSTEM, AND DETERMINED THAT THE FIRE DETECT CONTROL UNIT AND WARNING HORN WERE INTERMITTENT. REPLACED THE FIRE DETECT CONTROL BOX AND WARNING HORN.