As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PDX - FIRE SYSTEM FAULT CAUTION MESSAGE RECEIVED EN ROUTE. RAN CHECKLIST AND NO FURTHER MESSAGES APPEARED. MAINTENANCE FOUND THE "FIRE DET A" CIRCUIT BREAKER POPPED. RESET CIRCUIT BREAKER AND COMPLIED WITH OPERATIONAL CHECK. CHECKS GOOD. AIRCRAFT RETURNED TO SERVICE. NO PARTS REPLACED.