As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PER HEAVY CHECK T/C PERFORMED OPS TEST OF EMERGENCY LIGHTS VIA MCDU. FAULT BAT/EPSU (11WL) EMERGEN L PERFORMED T/S IAW TSM 33-51-00-810-855-A FOUND BATTERY FOR 11WL NEEDING TO BE REPLACED. REMOVED AND REPLACED BATTERY AT EPSU 11WL IAW AMM 33-51-38-000/400-002-A OPS TEST GOOD VIA MCDU. CIDS POWER UP INTERFACE TEST GOOD. A/C OK FOR SERVICE. (AIRCRAFT WAS RETURNED TO SERVICE)/END/