As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: DURING EMERGENCY POWER SUPPLY UNIT SYSTEM TEST FOR CABIN INTERCOMMUNICATION DATA SYSTEM 1 SYSTEM FAULTED EMERGENCY POWER SUPPLY UNIT (17WL) OVERWING DOOR LEFT. REMOVED AND REPLACED EMERGENCY POWER SUPPLY UNIT 17WL PER AMM 33-51-38-400-001-A.