As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PDX - FLIGHT 2131 - AIRCRAFT RETURNED TO FIELD WHEN AFTER TAKEOFF THE NR 2 ENGINE HYDRAULIC PUMP CAUTION LIGHT ILLUMINATED ON TAKEOFF. MAINTENANCE INSPECTED THE AIRCRAFT AND FOUND AIR IN THE NR 2 HYDRAULIC SYSTEM. THE HYDRAULIC SYSTEM WAS BLED AND OPERATIONAL CHECKS WERE PERFORMED. OPERATIONAL CHECKS WERE GOOD AND THE AIRCRAFT WAS RETURNED TO SERVICE. NO PARTS REPLACED.