As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) WHEN CONDUCTING THE AILERON CONTROL CHECK DURING TAXI, THE FLIGHT CREW DETECTED UNUSUALLY HIGH FORCE REQUIRED IN ROLL. CREW COULD ALSO HEAR A SERVO NOISE WHEN MOVING THE AILERONS. REPLACED THE AUTOPILOT ROLL ACTUATOR & THE SYS WAS TESTED SERVICEABLE. THE AIRCRAFT SUBSEQUENTLY RETURNED TO SERVICE.