As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AUTO PILOT B WILL NOT ENGAGE. GROUNDED - YES. REMOVED & REPLACED MCP REF B737-800 AMM 22-11-34. PERFORMED DFCS OPS TEST, REF AMM 22-11-00. PERFORMED ADDITIONAL TESTS FOR GROUP 11 AND GROUP 15. A/C RELEASED FROM MEL 22-1F. LAND VERIFY ACCOMPLISHED REF AMM 22-11-00-700-801. ALL TESTS PASSED. A/C RETURNED TO CAT III STATUS.