As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED. LEFT HAND OVER WING EXIT EMERGENCY POWER SUPPLY UNIT DISPLAYED , "UNIT FAULT" DURING TEST TASK 20A OF CARD 26L00005044. REPLACED EMERGENCY POWER SUPPLY UNIT AND ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK PER AMM 33-51-38.