As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FIRE DET FAULT ON STATUS PAGE/MAINT INTERMITTENT ON/OFF THROUGHOUT FLIGHT. PERFORMED FDCU-2 FAULT REVIEW, SHOWED SEVERAL FLT LEGS "UPRIGHT FIRE DET ASSY A" AND "LOOP A FAULT". R & R HARNESS ASSY PER MM 71-50-04 AND TERMINAL BLOCK. NR 2 ENG FIRE DETECTION SYSTEM OPS CK NML PER MM 26-11-02. REQUIRED. M427874 ASSIGNED. PLACARD INSTALLED.