What was found
AT CRUISE, LH FMC FAILED. VTK ON CAPT, BOTH CDUS MISSING FMC PROMPT. IT LASTED ABOUT 1 MIN THEN CORRECTED ITSELF.*ON TAXI IN WE GOT A FMC DISAGREE MESSAGE THAT CLEARED WITHIN 30 SECONDS. GROUNDED - YES. CONFIRMED INFLT FAULT FROM FMCS BITE FOR "L FMC" ON LAST LEG ONLY, NO CURRENT FAULTS. PERFORMED OPS TEST OF FMCS REF B737-800 AMM 34-61-00-710-801, OPS TEST GOOD. NO RECENT FAULTS. A/C OK FOR SERVICE.