As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SEA FLIGHT NR 2332: DURING HYD NR 3 ISO VALVE TEST, 33 PRESSURE FLUCTUATES AND DROPS WHILE WORKING ELEVATOR. PRESSURE FALLS TO ZERO. MAINTENANCE REMOVED AND INSTALLED A SERVICEABLE NR 3 HYD SYSTEM PRESSURE SWITCH IAW Q400 AMM 29-12-31-000-801 AND 29-12-31-400-801. PERFORMED OPS TEST OF NR 3 HYDRAULIC SYSTEM IAW Q400 AMM 29-12-01-710-801. OPS TEST GOOD. LEAK CHECK GOOD. AIRCRAFT RETURNED TO SERVICE.