As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: DURING EMERGENCY LIGHT OPS TEST, CIDS INDICATED EMERGENCY POWER SUPPLY UNIT (12WL) FAILED. MAINTENANCE TROUBLESHOT PER AIRBUS A319 TSM 33-51-00 AND REPLACED EMERGENCY POWER SUPPLY UNIT (12WL) PER AMM 33-51-38 AND PERFORMED SATISFACTORY OPERATIONAL CHECK.