As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING DAILY CHECK, AFTER FLT 329 IN BWI, MAINTENANCE PERSONNEL DISCOVERED THAT ROWS 21, 25 & 27 ON LT SIDE OF AIRCRAFT AND THE L2 & R2 (LT AND RT REAR DOORS) EMERGENCY LIGHTS DID NOT ILLUMINATE WHEN TESTED. THE EPSU (EMERGENCY POWER SUPPLY UNIT) BATTERY PACK AT THE L2 DOOR WAS REPLACED AND TESTED I/A/W AMM 33-51-38-401. THE AIRCRAFT WAS RETURNED TO SERVICE.