As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED ON TAXI, SMOKE IN COCKPIT ELECTRICAL BURNING SMELL IN COCKPIT ONLY. CONTRACT MAINTENANCE FOUND FAULTY AP PUSHBUTTON SWITCH ON AUTOPILOT CONTROL PANEL. REMOVED AND REPLACED FLIGHT GUIDANCE CONTROLLER IAW EMB145 MM 22-11-01. OPS CHECK GOOD. AIRCRAFT RETURNED TO SERVICE.