As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT CONTROL CHECKS, PRIOR TO FLIGHT, IT WAS DISCOVERED THAT THE UPPER RUDDER CHANNEL B FAILED THE PRE-FLIGHT CHECKS. THE UPPER RUDDER POSITION WOULD STAY FULLY DEFLECTED UNTIL RESET. THE MAINTENANCE FOUND THE CHANNEL B RUDDER POSITION SENSOR DEFECTIVE. THE SENSOR WAS REPLACED AND OPS AND TRAVEL CHECKS WERE NORMAL.