What was found
PDX FLIGHT NR 2080, AFTER TAKEOFF, RECEIVED NR 2 ENG HYD PUMP CAUTION LIGHT. COMPLIED WITH CHECKLIST AND IN SO DOING DETERMINED NR 2 HYDRAULIC PRESSURE AND QUANTITY WERE BOTH NORMAL. THE CAUTION LIGHT CYCLED ON AND OFF FOR SEVERAL MINUTES THEN REMAINED OUT FOR REMAINDER OF FLIGHT. MAINTENANCE REPLACED NR 2 ENGINE HYDRAULIC PUMP PRESSURE SWITCH. GROUND RUN ENGINES. MOVED FLIGHT CONTROLS FOR SEVERAL MINUTES. NO DEFECTS NOTED AT THIS TIME. CAUTION LIGHT NEVER ILLUMINATED FOR NR 2 ENGINE HYDRAULIC PUMP. LEAK CHECK GOOD. AIRCRAFT RETURNED TO SERVICE.