As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED. CABIN ODOR DURING CLIMB OUT. DISAPPEARED THEN REAPPEARED DURING DESCENT. AIR COMING THROUGH COCKPIT VENTS FELT OILY. ACCOMPLISHED JOB CARDS 26L00021001 AND 26L00021002, FOUND AUXILIARY POWER UNIT AS SOURCE OF CABIN ODOR. REMOVED AND REPLACED APU PER JOB CARD 26L31049003.