As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED: AUTOPILOT ENGAGED UNCOMMANDED AND PITCHED AIRCRAFT NOSE DOWN. AUTOPILOT WOULD NOT REMAIN DISENGAGED. MAINTENANCE HAS NOT TROUBLE SHOT SYSTEM TO DETERMINE CAUSE OF FAILURE. AUTOPILOT SYSTEM WAS INSTALLED 74.4 HOURS AND 32 DAYS BEFORE OCCURRENCE.