As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMBOUT WITH AUTOPILOT ENGAGED THE "STAB OUT OF TRIM" ILLUMINATED, WE RAN THE QRH AND DISCOVERED THE ELECTRICAL STAB TRIM WAS INOP ON BOTH YOKES. GROUNDED - YES. AIR TURNBACK - RESET INTERNAL STM LOGIC PER B737-800 FIM 27-41 TASK 802, OPS CHECK GOOD, STAB TRIM OPERATES NORMAL.