As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING MAINTENANCE IT WAS DISCOVERED EPSU EXT LOAD EMERGENCY RT AND EPSU EXT LOAD LT FAILURE MESSAGES FOR EMERGENCY LIGHT SYS CHECK. R & R LT, 10WL, EPSU IAW AMM 33-51-38 . REMOVED AND INSTALLED EPSU AT 12WL. PERFORMED OPS TEST OF EMERGENCY LIGHTS IAW AMM 33-51-00-710-001-A. OPS TEST OK.