As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT AND CREW REPORTED FUMES IN CABIN/ COCKPIT AREA AND RETURNED TO LAND AS A PRECAUTION. THE MECHANIC WAS CALLED TO INVESTIGATE. THE DOOR SEALS AND ATTACHING HARDWARE WERE EXAMINED FOR DEFECTS. THE METRO AIR / HEATING SYSTEM WAS INSPECTED FOR DEFECTS IN THE HOSES AND FITTINGS. NONE WERE FOUND. IT IS SUSPECTED LOW AMBIENT TEMPERATURES AND A TAILWIND CAUSED SOME FUMES TO BE DRAWN INTO THE CABIN AREA.