As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AUTOPILOT PITCH TRIM MESSAGE ILLUMINATED WHILE DESCENDING TO FL 270. AFTER FOLLOWING QRH PROCEDURE MESSAGE EXTINGUISHED. RETURNED TO SLC. AUTOPILOT PITCH TRIM SYSTEM OPS CHECKS GOOD. REPLACED THE STABILIZER TRIM ACTUATOR AND MOTOR CONTROL UNIT.