Bosch SKS60E18RU error E01 ⇐ Bosch

[bolt]

PMM Bosh SKS60E18RU, manufactured in 2012, during operation the heating element with the pump was changed three years ago, it started randomly displaying error E01 - regardless of the program, at a random moment in the cycle an error pops up, it may work for 5 minutes, maybe 15, but the result is clear - E01
I cleaned the machine - I poured boiling water over the drain, then took it apart, cleaned everything from the inside, and at the same time checked the heating element and the pump - the resistance is normal, there is no play. I removed the electronic control unit, cleaned all the contacts, cleaned all the connectors where possible, after assembling the PMM worked two cycles and started giving error E01 every other time - it will give an error, if you restart it, it will work the cycle. This went on for five cycles, after which the PMM decided to refuse to work at all, and now, after turning it on, after a couple of seconds it immediately gives error E01 with a click of clearly some kind of relay. where to look, what to dig?

[Artem]

Error E01/defect of the control unit in the circulation pump circuit. Faults/circulation pump controls in the control unit, circulation pump, wiring or contacts in the circulation pump circuit. Possibly low or unstable voltage in the electrical network. In rare cases, this is a failure of the control unit / completely de-energize the PMM for 30 minutes /

[bolt]

Thank you, Google didn’t give me anything sensible, even based on the error code
Faults
1. Control elements for the circulation pump in the control unit - unknown
2. circulation pump - normal
3. Wiring or contacts in the circuit of the circulation pump - normal.
4. Low or unstable voltage in the electrical network is possible - normal
5. In rare cases this is a failure of the control unit, completely de-energizing the PMM for 30 minutes does not help.
conclusion - most likely the circulation pump controls in the control unit are faulty.
question: - where to look for the pump controls on the control unit board ?how to test them?