As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING C-04 CHECK THE LT OVERWING EMERGENCY POWER SUPPLY UNIT INDICATED A FAULT. MAINTENANCE REMOVED AND REPLACED LT OVERWING EMERGENCY POWER SUPPLY UNIT (11WL) AND BATTERY PACK IAW AMM TASKS 33-51-38-000-001 AND 33-51-38-400-001, OPERATIONAL CHECK WAS GOOD.