As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED STABILIZER TRIM AND MACH TRIM MESSAGES DURING CLIMBOUT. CREW RETURNED TO FIELD AND LANDED WITHOUT INCIDENT. MAINTENANCE TROUBLESHOT, R & R HORIZONTAL STABILIZER TRIM CONTROL UNIT (HSTCU) AND PERFORMED CHECKS IAW MM. ACFT RELEASED FOR SERVICE.