As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING A POST FLIGHT OF AIRCRAFT, THE NR 2 ENG FIRE LOOP FAILED AN OPS TEST. GROUNDED THE AIRCRAFT. REMOVED AND REPLACED THE FIRE DETECTION LOOP. OPS CHECKED WITH NO DEFECTS NOTED. THE AIRCRAFT WAS RETURNED TO SERVICE, IAW AMM 26-10-00.