As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE BOARDING AND AT THE GATE IN CLT, CREW REPORTED SMOKE AND FUMES IN CABIN. PASSENGERS DEPLANED THROUGH MAIN CABIN DOOR. CREW REPORTED APU SHUT DOWN AUTOMATICALLY AND NOTED OIL ON GROUND UNDER AFT EQUIPMENT BAY. MAINTENANCE INSPECTED AND FOUND APU OIL COOLER LINE NOT ATTACHED. MAINTENANCE REMOVED AND REPLACED APU AND PERFORMED CHECKS USING AIRCRAFT MAINTENANCE MANUALS. AIRCRAFT RELEASED FOR SERVICE.