As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING HEAVY MAINTENANCE: 11WL BATTERY FAULTED. REMOVED AND REPLACED THE BATTERY IAW AMM 33-51-38-00-002-A/400-002-A. PERFORMED AN OPS CHECK IAW 33-51-00-710-001-A. 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 N1077.