As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APPROX 45 MINUTES INTO FLIGHT FL370 IN CRUISE, SMOOTH AIR AUTOPILOT A DISCONNECTED AUTOPILOT B ENGAGED NO PROBLEM. AFTER 5 MINUTES RE ENGAGED AUTOPILOT A FOR REMAINDER OF FLIGHT WITH NO FURTHER PROBLEMS. GROUNDED - YES. ACCOMPLISHED REQUIRED TESTS B737-800 AMM 22-11-00/21 OPS CHECK GOOD ALSO ACCOMPLISHED HGS TEST HGS 4000 SMM 34-36-00 OPS CHECK GOOD AIRCRAFT IS AUTOLAND & HGS CAT III QUALIFIED.