What was found
LEFT FMC FAILED AT CRUISE ALTITUDE WITH VTK, THEN MAP ON CAPTAIN'S NAV AND NO FMC DATA ON EITHER CDU. AFTER 1 MINUTE, NORMAL FUNCTION RETURNED WITH NO CREW ACTION. ACFT GROUNDED. REBOOTED THE LT FMC PRECAUTIONARY. LT FMC BITE TEST OK, IAW FIM 34-61TASK 804. THE FAULT WAS ONLY ON THE LT SIDE & THE SYSTEM RESET ITSELF IN FLIGHT, BOTH SIDES REBOOOTED TO MATCH UP. NO FAULTS NOTED ON RT FMC.