What was found
ENG #2 VIBRATION INDICATOR DISAPPEARED INFLIGHT. GROUNDED - YES. ACCOMPLISHED AAVM SYSTEM BITE TEST, "N2 TACHO LOSS E2" LOGGED REF B737-800 AMM 77-31-00-970-803-F00 AND B737-800 FIM 77-31 TASK 801. TROUBLESHOOT PER FIM 77-31 TASK 805, B737-800 WDM 77-31-21 AND 77-12-21, FOUND T422 , N2 SPEED SENSOR INTERNAL RESISTANCE FAILS. REMOVED AND REPLACED #2 ENGINE N2 SPEED SENSOR REF AMM 77-11-02/401. RUN THE ENGINE AT IDLE-POWER AND PERFORMED LEAK CHECK, NO LEAK NOTED. EEC BITE CHECK GOOD. NO FAULT NOTED AT THIS TIME. ETOPS SIGNIFICANT SYSTEM GROUND VERIFICATION GOOD.