As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON PREFLT LNAV/VNAV WILL NOT ENGAGE. GROUNDED - YES. ACCOMPLISHED DFCS BITE REF B737-800 FIM 22-11 TASK 801 DFCS FAULTED 22-11063, ACCOMPLISHED FIM 22-11 TASK 817, MCP TEST FAULTED SAME 22-11063. REMOVED AND REPLACED MCP REF B737-800 AMM 22-11-34 ALL OPS CKD NML. ALL GND TESTS PASSED.