Citroen C5 X7 electric tailgate opens slightly but stops

[piliotov]

Hello Guys,
I have my Citroen C5 2011 since 1 year now, and never experienced any problems with the tailgate. Until a month ago, when I tried opening my tailgate after the car was in for a service of the oil and so on. But it wouldn't open more than 10-15 degrees and stops. Before anything else, the car is 2011 and has electric tailgate. I have given it to a mechanic he told me that maybe the cables were bad and after opening a certain amount they got disconnected, he tried that it wasn't the case, and he gave me the car back. I have read the manual that there is memory, but I wasn't successful with that. If you can explain how should I reset the position to be fully open I would appreciate it.
Then I have disassembled the whole door and the mechanism as well. I have greased the insides because thought that there was too much friction in the sleeves of the metal cables, but it didn't solve the issue. The most interesting thing is that I have disassembled the motor and left it hanging, I have closed the door and pressed the outside button to open it. As you imagine the motor started spinning but since disconnected it didn't stop spinning until I have lifted the door to the above mentioned 10-15 degrees. Then it stops, so surely it is either a faulty sensor for height, or a memory, please help me solve the issue!!!

Thanks in advance, I appreciate your time to read this and help me!