As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EN ROUTE FORM LRD TO TOL, WHEN THE LANDING GEAR WAS RETRACTED THE FLIGHT CREW NOTICE A VIBRATION IN THE NOSE OF THE AIRCRAFT. THE FLIGHT CREW CYCLED THE LANDING GEAR BUT THE VIBRATION REMAINED PRESENT. THE AIRCRAFT RETURN TO LRD FOR AN UNEVENTFUL LANDING. MAINTENANCE INSPECTED THE AIRCRAFT WHICH REVEALED THE LEFT NOSE LANDING GEAR DOOR OPEN. MAINTENANCE CLEANED, LUBRICATED AND SECURED THE TELESCOPING DOOR ROD. THE AIRCRAFT WAS RETURNED TO SERVICE.