Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove electrical connector to DHW sensor

Measurement:

Measure the resistance (continuity) across the DHW
sensor harness leads.
Connections are:
CN2 connector pins 46 & 47 to corresponding connection
on DHW sensor connector.
Expected resistance is continuity (zero resistance).