As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT CAPTAIN'S NAV DISPLAYED VTK FOLLOWED BY MAP FAILURE FLAG. DURING THE FAILURE THERE WAS NO FMC DATA ON BOTH CDUS. AFTER 90 SECONDS CAPTAIN`S FMC RETURNED TO NORMAL OPS AND FMC DATA RETURNED TO BOTH CDUS. GROUNDED - YES. RAN B737-900 FIM TASK 34-61 TASK 836, OPS RESTORED. CHECKS OK, REFERENCE SAME.