Hi @cyrex86
I would check if the [https://www.bosch-home.com/za/supportdetail/product/SKS50E32EU/13#/Tabs=section-spareparts/Togglebox=tb0405/|flow through sensor] (part #0405) is OK. It may be intermittently failing
As water passes through the sensor it causes the reed contacts to send pulses to the control board which counts them so that it knows how much water is entering the machine.
What can happen is that the reed contacts can stick or not make good contact so that if the control board cannot determine the amount of water that has entered, it aborts the program.
You can test if the sensor is working properly, by removing it from the machine and then connecting an Ohmmeter to the reed contacts of the sensor. By blowing air into the sensor inlet tube, this causes the wheel to turn. The wheel has a magnet attached to it and when it spins every revolution causes the contact to make and the release.
You can see the pulses on the meter