As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UNUSUAL SMELL NOTED IN THE CABIN. SUPPLEMENTAL DATA UPDATE AFTER ACCOMPLISHMENT OF TROUBLESHOOTING PROCEDURES, FOUND APU OIL PRESSURE SWITCH LEAKING AND OIL BEING INGESTED INTO APU AIR INLET. SWITCH WAS REPLACED AND NO FURTHER SMELL NOTED.