As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: PILOT REPORTS FLIGHT DIVERSION TO LGA ON ACCOUNT OF AN UNCOMMANDED RUDDER DEFLECTION WHILE AT CRUISE. UPON LANDING, THE CREW RECEIVED A "FLIGHT CONTROL - NO DISPATCH" MESSAGE. MAINTENANCE REMOVED AND REPLACED THE LOWER RUDDER POWER CONTROL UNIT IAW AMM 27-22-01-000-400-801-A. OPS CHECK GOOD. LEAK CHECK PASSED.