As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ORD FLT 5871 - THE CREW REPORTED A MAIN PITCH TRIM FAIL MESSAGE IN FLIGHT. THE AIRCRAFT DIVERTED INTO CAK AND LANDED WITHOUT INCIDENT. MAINTENANCE INSPECTED AND REPLACED THE FIRST OFFICER'S PITCH TRIM SWITCH. OPERATIONAL CHECKS WERE GOOD.