As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON DEP, HDG BUG WAS STUCK ON RWY HDG. UNSELECTABLE IN HDG MODE OR IN LNAV. F/D HDG MODE WAS NOT WORKING. APPROX 5 MINS LATER, HDG WAS AGAIN SELECTABLE. F/D HDG MODE AVAILABLE. NO FURTHER ISSUES. GROUNDED - YES. ACCOMPLISHED B737-900 FIM 22-11 TASK 803. OPS TEST NORMAL REF MCP LRU TEST REF B737-900 AMM 22-11-00-740-801.