As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 5344 STL TO RDU. IN FLIGHT AT FL330 THE FLIGHT CREW RECEIVED AN AUTO PILOT FAIL AND YAW DAMPER FAIL MESSAGE FOLLOWED SHORTLY AFTER WITH A RUDDER 1-2 INOP MESSAGE. THE CREW RAN THE QRH PROCEDURE AND DIVERTED TO SDF. MAINTENANCE CHECKED THE WIRING FROM THE PRESSURE SWITCHES TO THE DAU, AND THE RUDDER PCU SOLENOID TO THE BULKHEAD WITH NO DEFECTS NOTED. THEN THE DAU NR 2 WAS REPLACED AND BOTH RUDDER PRESSURE SWITCHES WITH NEWER STYLE SWITCHES. THE TEST FLIGHT THAT FOLLOWED WAS SUCCESSFUL WITH NO FURTHER DEFECTS NOTED.