As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON FLIGHT 4258, DURING PRE-FLIGHT CREW NOTED EMERGENCY LIGHTS OFF OF BATTERY 3 INOPERATIVE. AIRCRAFT REMOVED FROM SERVICE. REINSERTED PIN "D" AT CONNECTOR P8031, OPERATION CHECK GOOD IAW EMB-140 AMM 33-50-00. AIRCRAFT RETURNED TO SERVICE.