As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON DESCENT INTO SMF, RECEIVED AN AP PITCH TRIM CAUTION MESSAGE AND A STAB TRIM 1 STATUS MESSAGE. COMPLIED WITH QRH AND RECONNECTED STAB TRIM NR 1. AFTER 5 MINUTES THE MESSAGE REOCCURED. RETURNED TO LAX. REPLACED HSTCU WITH SERVICEABLE UNIT. OPS CHECK GOOD AT THIS TIME. S/N OFF: 846.