As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: DURING PERIODIC SERVICE CHECK, MAINTENANCE FOUND EMERGENCY POWER SUPPLY UNIT EMERGENCY LEFT FAULT MESSAGE AND MULTIPLE FLOOR PROXIMITY EMERGENCY LIGHTS INOPERATIVE. REPLACED EMERGENCY POWER SUPPLY UNIT 11WL AND ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK.