As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING DESCENT, FIRST OFFICER`S CDU WENT BLANK AND EVERY LIGHT ON THE KEY PAD ILLUMINATED. THERE WAS NO VTK AND THE MAPS WERE OTHERWISE NORMAL. AFTER A WHILE THE CDU DISPLAYED A "BIT: PASS" AND THE CDU RETURNED TO NORMAL. ACFT GROUNDED. COULD NOT DUPLICATE, OPS GOOD IAW AMM 34-61 TASK 804. GROUND VERIFICATION SUCCESSFUL IAW FIM 34-61 TASK 804.