As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW NOTICED SMOKE IN THE CABIN AFTER APU STARTED. ORD MX WAS THEN ABLE TO DUPLICATE PROBLEM BUT IT WAS NOT SMOKE LIKE THE CREW CALLED, BUT A STRONG ODOR IN THE CABIN DURING APU START. WHEN APU WAS SHUTDOWN THE ODOR WENT AWAY. APU WAS CAUSING ODOR IN CABIN DURING START UP. MEL APU