As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED AN UNCOMMANDED STAB TRIM MOVEMENT DURING TAKEOFF ROLL, CREATING A TAKEOFF CONFIG WARNING. TAKEOFF WAS ABORTED AND ACFT RETURNED TO GATE WITHOUT FUTHER INCIDENT. MX INSPECTED IAW ACFT AMM AND REMOVED AND REPLACED THE HSTCU. OPS CHECKS WERE CARRIED OUT IAW THE AMM AND NO FURTHER DEFECTS NOTED. ACFT RETURNED TO SERVICE. FDR DOWNLOADED REQUESTED TO OPERATOR TO CONFIRM THE UNCOMMANDED MOVEMENT.