As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: WHILE EXECUTING THE ILS 17C AT DFW, VERTICAL AND LATERAL GUIDANCE WENT AWAY, AUTO PILOT DISCONNECTED AND AT STOPPED WORKING. DIVERTED TO TUL AND EVERYTHING HAPPENED AGAIN WHILE DOING THE ILS 18L. REMOVED AND REPLACED DIGITAL FLIGHT CONTROL SYSTEM MODE CONTROL PANEL PER AMM 22-11-34-400-801.