As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: LOCATION 13WL EMERGENCY POWER SUPPLY UNIT BATTERY FAILED BUILT IN TEST EQUIPMENT TEST IN REFERENCE WITH JOB CARD 26L00005005. REMOVED AND REPLACED EMERGENCY POWER SUPPLY UNIT BATTERIES AT LOCATION 13WL IN REFERENCE WITH AMM 33-51-38.