As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EWR---CO4361, CREW REPORTED AFTER TAKEOFF, LANDING GEAR WOULD NOT RETRACT. ALSO, HAD EICAS MESSAGE LG AIR/GND FAIL. MAINTENANCE FOUND NOSE LANDING GEAR LEG WOULD NOT FULLY EXTEND CAUSING THE LANDING GEAR NOT TO RETRACT AND THE LG AIR/GND FAILURE MESSAGE ON THE EICAS. REMOVED AND REPLACED NOSE LANDING GEAR LEG IAW EMB145 MM 32-20-01. OPS AND LEAKED CHECKED GOOD. AIRCRAFT RETURNED TO SERVICE.