As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PDX - IMMEDIATELY AFTER GEAR RETRACTION, THE NOSE GEAR TRIED TO EXTEND 2-3 TIMES. THE RED AND GREEN LIGHTS FLASHED REPEATEDLY FOR 10 - 15 SECONDS. GEAR STAYED UP NORMALLY. MAINTENANCE INSPECTED THE AIRCRAFT AND REPLACED THE DRAG STRUT PROXIMITY SENSOR. THE SENSOR WAS ADJUSTED AND A FUNCTIONAL CHECK OF THE LANDING GEAR WAS PERFORMED. FUNCTIONAL CHECKS WERE GOOD AND THE RII WAS COMPLIED WITH. AIRCRAFT RETURNED TO SERVICE.