What was found
DURING CRUISE AT FL400, A VIBRATION & AUDIBLE NOISE NOTED APPROX 2 HRS INTO FLT. AN ENGINE CONTROL FAULT MESSAGE DISPLAYED ON CAS. CHECKLIST FOLLOWED AND CAS MESSAGE EXTINGUISHED. SEVERAL MINUTES LATER, A DC GEN CAS MESSAGE DISPLAYED & CHECKLIST COMPLETED. UNABLE TO RESET CAS MESSAGE. VIBRATION FROM LT ENGINE CONTINUED, DIVERTED. LT THROTTLE BROUGHT TO IDLE WHICH REDUCED NOISE AND VIBRATION. LANDED AT DEPARTURE UNEVENTFULLY. R & R LT ENGINE STARTER/GENERATOR IAW MM 80-10-00. OPENED DRAIN CAP ON EEC PRESSURE SENSE LINE AND FOUND EXCESSIVE MOISTURE. REMOVED LINE AND RECONNECTED. RAN ENGINES, OPS CHECKED GOOD.