As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING WEEKLY CHECK, EMERGENCY LIGHTING SYSTEM TEST FAILED. EPSU BATTERY AFT L FAULT DISPLAYED ON CIDS PANEL AFTER TEST. CONDUCTED OPERATIONAL CHECK OF EMERGENCY LIGHTS IAW AMM 33-51-00-710-001A SEVERAL TIMES, UNABLE TO DUPLICATE FAULT.