As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF, THE LANDING GEAR WOULD NOT RETRACT. THE DOWN AND LOCKED LIGHTS AND THE HANDLE INTRANSIT LIGHT REMAINED ILLUMINATED. THE HYDRAULIC PUMP RAN CONTINOUSLY. MAINTENANCE REPLACED THE LANDING GEAR CONTROL VALVE AND PERFORMED LANDING GEAR SWINGS.