As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ALL THREE CEILING PANEL EMERGENCY LIGHTS AFT OF OVERWING EXIT DOORS AND BOTH RT AND LT AFT OF WING EMERGENCY EXTERIOR LIGHTS FAIL TO STAY ON. REMOVED AND REPLACED EMERGENCY BATTERY PACK 4 IAW CRJ900 AMM 33-51-17. OPS TEST S/W OF EMERGENCY LIGHTS IAW CRJ900 AMM 33-51-00. OPS CHECK GOOD.