What was found
AT FL340 A/P 2 SELECTED. WE RECEIVED ALERT MESSAGE AND FOUND VTK WAS ANNUNCIATED ON F.O. SIDE PFD AND LNAV/VNAV BECAME DISENGAGED AND WE WERE UNABLE TO RE-ENGAGED, WE SELECTED A/P 1 AND LNAV/VNAV WERE ABLE TO BE ENGAGED ALL WAS NORMAL, AND FLAGS DISAPPEARED. GROUNDED - YES. PERFORMED FMCS BITE FOR R/H SIDE PER B737-900 FIM 34-61 TASK 801. HAD MULTIPLE FAILURES FOR FMC #2 ETHERNET WRAP MESSAGES. DUE TO HISTORY, REMOVED AND REPLACED FMC #2 PER B737-900 AMM 34-61-02. PERFORMED GOOD SOFTWARE LOAD, SOFTWARE CHECK AND GOOD OPS TEST PER AMM 34-61-02-400-801. GROUND VERIFICATION TEST IS GOOD.