As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: REF PS CHK OPS TEST OF EMERGENCY LIGHTS ITEM #26, TEST FAILS "EPSU BATTERY EMERG R" MESSAGE. SUSPECTED BATTERY AT 12WL. REMOVED AND REPLACED EPSU BATTERY AT 12WL (R) IAW AMM 33-51-38 & 33-51-00 OPS TEST. GOOD - NO FAILURE MESSAGES PRESENT.