As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED WHEN THE APU WAS TURNED ON FOR LANDING, IT CAUSED THE CABIN TO FILL WITH SMOKE. CREW FOLLOWED THE QRH, TURNED OFF THE APU AND LANDED WITHOUT INCIDENT. MAINTENANCE INSPECTED AND FOUND THE OIL LEVEL TO BE OVERSERVICED. MAINTENANCE PROPERLY SERVICED THE OIL LEVEL IN ACCORDANCE WITH THE AIRCRAFT MAINTENANCE MANUAL. AIRCRAFT WAS RELEASED FOR SERVICE.