As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
TOXIC SMOKE SMELL SEEMS LIKE IT IS COMING THROUGH THE WEMACS. SEEMS TO BE LESS INTENSE WITH COCKPIT PAC TURNED OFF. TROUBLESHOT TO APU INTERNAL OIL LEAK. REMOVED OLD APU AND INSTALLED A REPAIRED APU IAW MM 49-10-00. OPS AND LEAK CHECKED GOOD.