As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAH - FLIGHT 2668, THE CREW REPORTED A RUDDER 1 & 2 INOP MESSAGE IN FLIGHT THREE TIMES. THE AIRCRAFT RETURNED TO IAH WHERE IT LANDED WITHOUT INCIDENT. MAINTENANCE REMOVED AND REPLACED THE RUDDER PCU, OPERATIONALLY TESTED WITH NO DEFECTS. AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE.