As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PDX - FLIGHT 2354 - AIRCRAFT RETURNED TO FIELD WHEN AFTER TAKEOFF THE GEAR FAILED TO RETRACT. THE GREEN AND RED LIGHTS ILLUMINATED, BUT THE CREW RECEIVED NO YELLOW LIGHTS. MAINTENANCE INSPECTED THE AIRCRAFT AND FOUND THE NOSE LANDING GEAR PROXIMITY SENSOR FLUCTUATING. THE NOSE LANDING GEAR WOW/NWCENT PROX SENSOR HARNESS WAS REPLACED. OPERATIONAL CHECKS WERE GOOD AND THE AIRCRAFT WAS RETURNED TO SERVICE.