As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED THAT AFTER TAKEOFF THE LANDING GEAR LEVER WOULD NOT MOVE UP. AT 400 FEET AGL THE CREW RECEIVED A LANDING GEAR AIR/GROUND FAIL MESSAGE ALONG WITH IC WOW 1/2 INOP MESSAGE. ALL OTHER INDICATION APPEARED NORMAL. THE CREW RETURNED TO KSDF AND LANDED WITHOUT INCIDENT. MAINTENANCE FOUND ALL FOUR LANDING GEAR PROXIMITY SWITCHES TO BE OUT OF LIMITS. ADJUSTED THE FOUR PROXIMITY SWITCHES AND OPERATIONAL CHECKS WERE GOOD WITH NO FURTHER DEFECTS NOTED.