As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT THE GATE WITH APU RUNNING THE PACKS CABIN BEGAN TO FILL WITH SMOKE. PACKS WERE TURNED OFF. REPLACED TURBINE BEARING CHIP DETECTOR PACKING. SERVICED OIL TO FULL. RAN APU SEVERAL HOURS, NO LOSS OF OIL. RAN ENGS, CLEARED PACKS OF OIL RESIDUE.