As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
C1 CHECK - DURING OPERATIONAL TEST OF EMERGENCY LIGHTS IAW AMM 33-51-00 THE PTP DISPLAY SHOWED "FWD UNIT FAULT L" AND "AFT BATTERY L". REPLACED EPSU 10WL AS PER AMM 33-51-38 PAGE BLOCK 0401 AND PERFORMED OPERATIONAL TEST OF EMERGENCY LIGHTS AND THE TEST IS OK.