As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER LANDING, BOTH FMCS DUMPED WITH "VTK" DISPLAYED ON CAPTAIN SIDE ONLY. BOTH SIDES-MENU HAD "FMC" PROMPT MISSING. AFTER A MINUTE OR SO, VTK WENT AWAY AND FMC PROMPT RETURNED TO MENU, HOWEVER ALL FMC DATA HAD DUMPED. GROUNDED - YES. INTERROGATED CDU FOUND GROUND FAULT FMC-L PGM. CW FIM 34-61 TASK 801 AND TASK 34-61 TASK 807 REF PARA (2)(A). AC IS OK FOR CONTINUED SERVICE.