As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER 4 HRS OF CRUISE FLIGHT, CAPT'S N.D. SHOWED AMBER "VTK" AND OTHER SIGNS OF L FMC FAILURE. AFTER RUNNING QRH PROCEDURE (FMC SELECTOR TO BOTH ON R) BOTH FMCS OPERATED NORMALLY. GROUNDED - YES. PERFORMED FIM 34-61 TASK 801, NO INFLIGHT OR SENSOR FAULTS SHOWN. AIRCRAFT SHOWS NO HISTORY LAST 30 DAYS.