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 CABIN INTERCOMMUNICATION DATA SYSTEM 1 EMERGENCY POWER SUPPLY UNIT SYSTEM TEST FOUND FAULTY BATTERY/EMERGENCY POWER SUPPLY UNIT (15WL) EXIT LEFT. REMOVED AND REPLACED THE EMERGENCY POWER SUPPLY UNIT BATTERY PER AMM 33-51-38.