Siemans Dishwasher E15 error - blocked internally

[PhilJW1]

I have a 3 year old Siemans dishwasher which stops just before the end of the cycle.

The pump/filters are clear and so is the drain hose.

An engineer tells me it is because of this (the orangey bit)

which he tells me is blocked and needs replacing (which isnt cheap!).

So my questions are

1. What does this do? I assume the unit drains from the bottom.
2. Is there no way of unblocking it without replacing the whole unit?
3. What causes it and how can I stop it happening again?

All help appreciated

 

[RichardMNZ]

Remove and clean it.

I like what this person does with the magnet.