As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: EPSU INT LOAD AFT L FAULT DURING SYSTEM CHECK. MAINTENANCE REPLACED EMERGENCY POWER SUPPLY UNIT 13WL (AALA202606229739) AND BATTERY (AALA202606221760) PER AMM 33-51-38. A SATISFACTORY OPERATIONAL CHECK WAS ACCOMPLISHED WITH NO ISSUES NOTED.