As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PIT - FLT 257 - PHL TO PHX - DURING CRUISE, FLIGHT EXPERIENCED A HIGH, NUMBER TWO ENGINE VIBRATION INDICATION PROBLEM. AIRFRAME VIBRATION WAS NOT DETECTED OR INDICATED. THE CREW REDUCED POWER ON THE NUMBER TWO ENGINE TO IDLE. SINCE AIRSPEED AND ALTITUDE COULD NOT BE MAINTAINED, THE FLIGHT DIVERTED TO PIT AND LANDED WITHOUT FURTHER INCIDENT. MAINTENANCE PLACED THE ENGINE VIBRATION INDICATION SYSTEM ON MEL.