As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMBOUT, THE CREW RECEIVED A LANDING GEAR DISAGREE MESSAGE WHEN RETRACTING THE GEAR AND THE GEAR CONTINUED TO INDICATE DOWN AND LOCKED. IAW THE QRH, THE CREW MADE AN UNEVENTFUL UNSCHEDULED LANDING AT THE FIELD OF DEPARTURE. MAINTENANCE R & R THE LANDING GEAR ELECTRONIC UNIT IAW AMM 32-32-01. ALL OPS CHECKS WERE GOOD AND NO FURTHER DEFECTS HAVE BEEN NOTED.