Electrolux ESL 67040R Dishwasher Error i20: Understanding Components and Resuscitation Steps

I decided not to give up as a layman, hence the request for help from professionals, I do not have the strength yet, but maybe with your help I will triumph. Some time ago, the dishwasher occasionally threw water under the door. For some time there is silence, as I gave the soda and I started a hot program.
Well, how did the I20 error appear at the end of the program and the quilting ... I did a service reset, but it did not do anything. I put pictures below, maybe in the future someone will also be useful to ask for a small lesson - what are the elements described by me with red numbers on the photos of my dishwasher and a hint to do to resuscitate her (I will add as a prelude that I am a layman). the last picture shows how dirt is in this plastic container, unless it must be such a color, thank you warmly and where and how the hydrostat looks if it is not on the photos, because I have heard that he is often the culprit.
I post photos:

In that case, first the lesson
1. Anti-block filter on mains supply
2. Salt container / dispenser
3. water separator (upper and lower propeller)
4. washing bowl (where you put the filter)
5. Drain pump
6. Washing pump
7. same as 1
8. I do not see the number on the photo
9. a solenoid valve, probably on the salt chamber
10. shield for the electrical harness going from the bottom of the door and module dishwasher

Now about i20
water drain error, in theory the dishwasher did not drain the water.
In practice, it may be an attempt to drain, the water will then be in the dishwasher, you need to check the trigger system (pump No. 5) for clogging, blockage or damage and a hose leading to and from it.

If the water does not stay, and an error is reported, the pipe between the washing bowl (No.4) and the hydrostat, the damaged hydrostat (quite a frequent problem) or the damaged electronics or the electronics itself may be contaminated, but leave it for the last resort.
You can find the hydrostat after removing the right side of the dishwasher at the door hinge, black or blue, put on white gray plastic

Thanks.
The matter is strange in that i20 there is every few washes, today, for example, I gave a reset and I set the rinsing program for 15 minutes, because until the end of the main wash when it appeared i20 20 minutes left The effect is that you managed to finish the laundry, what you think for me is magic because it is either good or bad, and here you can see the swing ...

The problem solved was to properly clean the hydrostatic chamber, it comes as a new lock.