As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BAN - DURING MAINTENANCE INSPECTION THE NUMBER 4 EMERGENCY LIGHT BATTERY WAS FOUND TO BE INOPERATIVE. MAINTENANCE REMOVED AND REPLACED THE AFFECTED EMERGENCY LIGHT BATTERY PACK, OPERATIONALLY CHECKED WITH NO DEFECTS, AND THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE.