As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: WHILE PERFORMING EPSU SYSTEM TEST GOT CLASS 1 BAT-EPSU FOR13WL AFT L FAULT. MAINTENANCE REPLACED THE AFT LEFT SLIDE PER JOB CARD 26L00025010 AND ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK WITH NO FAULTS NOTED.