As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT JB115 JFK-MSY AFTER 40 MINS IN FLIGHT AIRCRAFT RETURNED TO JFK DUE TO ENGINE 2 LP VIBRATION REACHED 4.0 UNITS ON CLIMB AND DURING CRUISE REACHED 2.7-2.9 AND SPIKED TO 3.1 WITH YELLOW EICAS MESSAGE. JFK MX PERFORMED IEVM FAN TRIM BALANCE IAW EMM 72-00-00-800-811 AND ENGINE VIBRATION CHECK IAW EMM 72-00-00-760-121 CHECK GOOD AND WITHIN LIMITS PER EMM 72-00-00-760-171. AIRCRAFT RETURNED TO SERVICE.