As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING HEAVY CHECK EPSU BATTERY 11WL (EMER L) FAILED EPSU SYS TEST. AIRCRAFT WAS NOT GROUNDED. REMOVED AND REPLACED EPSU BATTERY 11WL (EMER L) IAW AMM 33-51-38-000-002-A/33-51-38-400-002-A OPS CHECK GOOD. AIRCRAFT WAS RETURNED TO SERVICE.