As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: DURING ACCOMPLISHMENT OF EMERGENCY POWER SUPPLY UNIT SYSTEM TEST MAINTENANCE FOUND A BATTERY FAULT MESSAGE FOR EMERGENCY POWER SUPPLY UNIT 10WL. REPLACED BATTERY FOR EMERGENCY POWER SUPPLY UNIT 10WL AND ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK.