As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PDX - ON FLIGHT 2479, RETURN TO GATE, "BEFORE TAKE-OFF CHECKLIST," FO UNABLE TO MOVE AILERONS TO RIGHT (LEFT WORKED AS NORMAL) ON 3RD TRY TO RIGHT AILERONS MOVED NORMALLY AND CONTINUED TO MOVE FREELY. MAINTENANCE REMOVED AND REPLACED THE AILERON SERVO MOUNT. PERFORMED OPERATIONAL CHECK. NO DEFECTS NOTED. AIRCRAFT RETURNED TO SERVICE.