As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PDX - FIRE SYSTEM FAULT MESSAGE DISPLAYED. PLACED ON MEL 26-00-1. FOUND LEFT ENGINE LOOP "A" INTERMITTENT, OPEN OR SHORTED. MEL CONTINUED, FURTHER TROUBLESHOOTING REQUIRED. REPLACED THE FIRE LOOP A. OPERATIONAL CHECKS GOOD. AIRCRAFT RETURNED TO SERVICE.