As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WITH AUTOPILOT ENGAGED ON EITHER C/A OR F/O SIDE, AP MAKES UNCOMMANDED SLOW ROLL LEFT OR RIGHT. AUTOPILOT FAIL LIGHT ON MAP DOES NOT ILLUMINATE. REMOVED AND REPLACED THE AILERON AUTOPILOT SERVO IAW EMB120 MM 27-00-03. AUTOPILOT OPS CHECK GOOD IAW MM 22-10-00.