As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
YAW DAMPER AND AUTOPILOT WILL NOT ENGAGE. DISCONNECT AURAL ALERT KEEPS COMING ON. GA MODE COMES ON UNCOMMANDED. REMOVED AND REPLACED YAW TRIM MODULE OPERATIONAL CHECK OF THE AUTOPILOT SYSTEM OK AT THIS TIME IAW SAAB AMM 22-10-00. NO DEFECTS NOTED. AIRCRAFT RETURNED TO SERVICE.