As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: DURING EMERGENCY POWER SUPPLY UNIT SYSTEM TEST FAULT MESSAGE FOR ESCAPE SLIDE LEFT / EMERGENCY POWER SUPPLY UNIT 10WL FORWARD LEFT DISPLAYED. MAINTENANCE REPLACED THE L1 DOOR ESCAPE SLDE AND ACCOMPLISHED A SATISFACTORY OPERATIONAL TEST OF THE EMERGENCY POWER SUPPLY UNIT SYSTEM PER TASK CARD 26L00025010 WITH NO FAULTS NOTED.