As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: DURING MULTIPLE FAULT MESSAGES FOR EMERGENCY POWER SUPPLY UNIT 10WL DISPLAYED DURING SYSTEM TEST. MAINTENANCE FOUND THE L1 DOOR SLIDE LIGHTING SHORTED, REPLACED THE SLIDE AND ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK PER TASK 26L00025010 WITH NO FAULTS NOTED.