As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED. EMERGENCY LIGHT SYSTEM FAULT. "EPSU INT LOAD FWD L" OCCURED WHILE PERFORMING THE FUNCTIONAL CHECK DURING THE PS MAINTENANCE CHECK. REPLACED EMERGENCY POWER SUPPLY UNIT 10WL (AALA202012049014) AND 12WL (AALA202012079025), PER AMM 33-51-13. ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK.