As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
HYD PUMP AND ADP SHOW NO HYD PRESSURE WHILE RUNNING. FOUND ISOLATED ACMP PRESSURE VALVE STUCK. R & R THE VALVE IAW MM 29-11-08 AND RELAY K1 PANEL M1216. IAW STANDARD WIRE PRACTICES MANUAL 20-81-22. CLOSED THE VALVE PREVENTED PRESSURE TO GET TO PRESSURE SWITCH. SYSTEM CHECKED OK.