As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED. EMERGENCY POWER SUPPLY UNIT EMERGENCY LIGHT FAULT FOUND ON EMERGENCY POWER SUPPLY UNIT BUILT IN TEST EQUIPMENT CHECK FOR R1 SLIDE CHANGE. REMOVED AND REPLACED MID LEFT EMERGENCY POWER SUPPLY UNIT (11WL), PER AMM 33-51-13-840.