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 OPERATIONS TEST OF EMERGENCY LIGHTS, CABIN INTERCOMMUNICATION DATA SYSTEM 1 EMERGENCY POWER SUPPLY UNIT SYSTEM TEST DIR 1 ACTIVE CLASS 1 FAULT, BATTERY EMERGENCY POWER SUPPLY UNIT (10WL) FORWARD LEFT. REMOVED AND REPLACED CABIN EMERGENCY BATTERY AT 10WL PER AMM 33-51-38.