As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: WHILE PERFORMING OPERATIONAL TEST OF EMERGENCY LIGHTING SYSTEM PER AMM 33-51-00-710-001-A, TEST FAILS WITH MESSAGE "EPSU EXT LOAD EMER R". REPLACED RIGHT AFT EMERGENCY OVER WING LIGHT 62WL AND ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK PER AMM 33-51-15.