Siemens eq9 Pump no water

Hello, I need your knowledge!
I have read all about the eq9 but nothing has helped.
My question is: can you blow through the pump? All pipes and components are clean and have flow and I have replaced the flowmeter. The heating element has also been checked for leakage. When I switch the machine on, you can hear the brewing unit move and then the pump starts to run but no water comes out of the outlet. There is also no water in the hose coming from the water tank.
Please help me because I find coffee from a normal machine dreadful!
Thanks in advance

You should not be able to blow through the pump.
Does the valve of the water tank open? Is the sieve on which the water tank sits clean? Does water end up in the drip tray or is no water being drawn from the tank? What does the black hose on the brew group look like and is it still intact?