As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED DUE TO: ON DESCENT BELOW 10000', ENGINE NUMBER 1 VIBRATION INDICATED AS HIGH AS 4.5. RAN CHECKLIST, CONTINUED FLIGHT WITH THRUST LEVER AT IDLE. VIBRATION INDICATION NEVER WENT BELOW 2.5. INDICATION REPEATEDLY BLANKED AND CAME BACK ON. NO VIBRATIONS FELT FROM NUMBER 1 ENGINE; AIRCRAFT EMERGENCY LANDED SAFELY AT BWI. VERIFIED THROUGH ENGINE DESK MOC THAT VIBRATION INDICATION IS FAULTY. OPEN).