As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB-OUT OF LGA, LANDING GEAR WOULD NOT RETRACT. AIRCRAFT RETURNED TO LGA AND LANDED WITHOUT INCIDENT. INSPECTED GROUND SHIFT MECHANISM AND GROUND SENSING FUNCTIONS. SERVICED NOSE GEAR STRUT TO PROPER LEVEL AND OPERATIONAL CHECK GOOD.