As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PDX - AFTER GEAR RETRACTION "PROX SYSTEM" CAUTION MSG AND "PROX SYSTEM FAULT 2" STATUS MSG CAME ON. RETURNED TO FIELD IN PDX. PRIOR TO LANDING BOTH MSG'S WENT OUT LANDING WT WAS 65000 LBS. REMOVED AND REPLACED LANDING GEAR SELECTOR VALVE CONNECTOR, FOUND CONTAMINATED WITH SKYDROL, C/W OPERATIONAL TEST OF GEAR RETRACT AND EXTENSION CHECK NORMAL. AIRCRAFT RETURNED TO SERVICE.