What was found
AIRCRAFT NOT GROUNDED - CIDS (CABIN INTERCOMMUNICATION DATA SYSTEM) 1 TEST, BATTERY / EPSU (EMERGENCY POWER SUPPLY UNIT) 13WL AFT L CLASS 1 FAULT. REMOVED AND REPLACED EPSU 13WL BATTERY PER AMM 33-51-38, SYSTEM TEST PERFORMED OKAY, CIDS 1 TEST PASSED.