As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: DURING PERIODIC SERVICE CHECK EMERGENCY POWER SUPPLY UNIT SYSTEM CHECK FAILED WITH CODE (BATTERY EMERGENCY POWER SUPPLY UNIT 13WL AFT LEFT). REPLACED EMERGENCY POWER SUPPLY UNIT 13WL AND ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK PER AMM 33-51-38.