As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED AND IS IN CHECK FOR SCHEDULED MX. DURING INCOMING CHECKS FOUND EPSU BATTERIES 13 WL INOP, REPLACEMENT REQUIRED AS PER AMM 33-51-38-04 CONF 00 REV. 102 CORRECTIVE ACTION: REPLACED EPSU BATTERY 13WL IAW AMM 33-51-38-400-001 CONF 00 REV. 102. MX ACTION IS ACCEPTABLE.