#1 hydro pressure "X" on hydraulic systems page and dashes in CFDS, HSC sensors page.
Not much troubleshooting needed here. Hang a new sensor on the plug. If problem clears, get ready for a possible Skydrol bath (even with head pressure blown, I still received a "goodly" amount of fluid).
MD-10-10 ATA 29-12 Hydraulic Pressure Indication
Schematic Manual 29-10-1
Maintenance Manual 29-12-46-2
Equipment List ID "T2-39"