As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE CREW REPORTED SMOKE IN THE COCKPIT ON DEPARTURE. THE ACFT RETURNED TO DEPARTURE AND LANDED WITHOUT INCIDENT. MAINTENANCE INSPECTED AND PERFORMED ENGINE RUNS AND PRESSURIZATION CHECKS. COULD NOT DUPLICATE ANY DEFECTS. NO SMOKE OR ODOR IN THE COCKPIT WAS NOTED. THE ACFT WAS RELEASED FOR SERVICE.