As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AIRCRAFT WAS TAXING FROM TERMINAL TO RUNWAY WHEN SMOKE STARTED FILLING COCKPIT. ELECTRICAL COMPONENTS WERE TURNED OFF AND AIRCRAFT RETURNED TO TERMINAL. MAINTENANCE WAS CONTACTED AND FORWARD VENT BLOWER WAS REPLACED. GROUND CHECKED SERVICEABLE.