As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: BATTERY FAULT MESSAGE FOR EMERGENCY POWER SUPPLY UNIT14WL DISPLAYED DURING SYSTEM TEST. MAINTENANCE REPLACED BATTERY PER TASK CARD 26C00033004 AND ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK OF THE EMERGENCY LIGHTING SYSTEM WITH NO FAULTS NOTED.