As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING HEAVY MAINTENANCE, 13WL BATTERY FAULTED. REMOVED AND REPLACED THE BATTERY OF EPSU 13WL IAW AMM 33-51-38-00-002-A/400-002-A. PERFORMED AN OPS CHECK OF EPSU IAW 33-51-00-710-001-A BITE CHECKED OK. PERFORMED INTERFACE & POWER UP TEST OF THE CIDS IAW AMM 23-73-00-740-005-B, TESTED OK. WORK ACCOMPLISHED ON WO W004054 NR N1078.