As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE NOSE GEAR WOULD NOT RETRACT AFTER TAKEOFF. THE AIRCRAFT WAS RETURNED TO ORD WHERE IT LANDED WITHOUT INCIDENT. THE AIRCRAFT WAS JACKED AND THE NOSE GEAR WAS RETRACTED FOUR TIMES WITH NO DEFECTS NOTED. THE AIRCRAFT HAS FLOWN OVER TEN FLIGHTS WITHOUT A REPEAT OF THIS ANOMALY.