Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove connector X2 from the PCB
Remove connector to system pressure sensor

Measurement:

Measure for resistance across each wire of the system pressure sensor harness, pins 11,13,14 of X2 to the corresponding wire on the sensor connector. (e.g. orange lead (pin 11) X2 connector to orange lead of system pressure sensor connector).
Expect continuity / zero resistance on each wire.