Necht Dishwasher?

I hope you can help me.
I have very recently inherited a NECHT WQP12-9319 dishwasher and I do not
know the history of what work may have been done on it. I am reading an
error message of E3, have checked the heating element, which is working OK
and I now have been looking at the temperature sensors. There are 2 sensors
both with KSD 201 markings. I measure an open circuit on 1 which has a red
dot on the terminal face and also has 90/25 on one face of the hexagonal
brass head of the unit. The other sensor measures full-continuity and has
78/50 on one face of the hexagonal brass head of the unit and I suspect
this unit is faulty.

My questions are:
1. Do you know what sensors are required on my dishwasher?
2. Should both sensors be the same?
3. What is the correct specification for the sensors?
4. Can you supply the correct replacement sensors?

Thank you for whatever information you return with.