As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAH- AFTER TAKEOFF FLIGHT 3917 THE CREW NOTED SMOKE IN THE COCKPIT. THE CREW DECLARED AN EMERGENCY AND RETURNED TO IAH WITHOUT INCIDENT. IAH- MAINTENANCE REMOVED AND REPLACED THE GROUND COOLING FAN, PERFORMED A OPERATIONAL CHECK, NO DEFECTS NOTED AND THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE.