General malfunction after short circuit at ESAM6700

Hello everybody,
I got a used ESAM 6700, it required a decalcification which could not be done because the water ran directly into the drip tray. After replacing the solvenoid valve on the steam heating system this was not possible, but since then it refused the decalcification process. Indicated directly that it was finished without rinsing. After that a message came up concerning the grinder too fine and something with water... ...and press ok. Then I disassembled and cleaned/greased the brewing group and the brewing piston as well. Also the exhaust air slaughterhouse was completely closed and is now also cleaned. When I assembled everything, I found a loose grounding cable leading from the steam heating to the 2 way valve behind the display. After researching the network I found pictures where it is connected to the thermoblock together with another grounding cable, I followed this example. When switching on the
device there was a short circuit! To the
actual state; the device starts, display
works, test mode also.

From this tested, pump without reaction, brewing group without function,

2-way valve without function.
How can I now check the ohmic values? What do I set my meter to and what should it display?
Plug on or off?

How

would you proceed?
Addition to me, hobby screwdrivers on household appliances of any kind and car repairs. Electrical understanding is
available
within certain limits
.

Measuring device

availableThanks
in advance!

That someone loosens the protective earth cable and then sells such a machine probably without any hint, is quite frightening! from
the logic of it, one of the two heaters will most likely have a body-closure. It can be measured. The resistance value between one of the heater connections and the housing should ideally not be measurable, i.e. it should show infinitely many ohms. At values in the kOhm range the RCD switch already triggers. If the error possibly only affects the steam heater, it is cheaper and easier
to repair.
Good luck (or continue asking questions)