As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT 3906 FROM IAH TO LIT THE CREW NOTED THAT THE NR 2 ENGINE/ LOOP -B- FAULT IN FLIGHT. MAINTENANCE REMOVED AND REPLACED THE DETECTOR BOX, PERFORMED A OPERATIONAL CHECK OF THE ENGINE FIRE DETECTION SYSTEM, NO DEFECTS NOTED. THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE.