As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) STAB TRIM CHANNEL NR 2 WILL NOT ENGAGE & MACH TRIM CATUION MESSAGE AT THE GATE. REPLACED THE HSTA AND THE MCU ON SPEC.NOTE: DURING REPLACEMENT, FOUND THE STABILIZER SURFACE TO BE EXCESSIVELY STIFF TO MOVE. STABILIZER PIVOT LUBRICATED. A/C BACK IN SERVICE.