As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
A/P A DISENGAGED AT CRUISE. IT WOULD NOT INITIALLY REENGAGE. AFTER TURNING BOTH F/D OFF AND USING THE DISENGAGE LEVER, WE WERE ABLE TO REENGAGE. GROUNDED - YES. RUN B737-800 FIM TASK 22-11 TASK 801. FMC INT FAULT REST & TEST A - FCC & A/P A OK REF FIM 22-11 TASK 801.