As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT IN BASE MAINTENACE: OPERATIONAL CHECK OF EMERGENCY LIGHTS FAILS. FAULT CODE BAT/EPSU (10WL) FWD L. 33-51-00. REMOVED AND REPLACED THE EMERGENCY POWER SUPPLY UNIT (AALA202007249003) AND ITS BATTERY (AALA202007249002) IN REFERENCE TO THE A319/A321 AMM 33-51-38 PERFORMED OPS CHECK OF THE EPSU THRU BITE CHECK IAW AMM 33-51-00 SYSTEM OK.