Hi Hassan, Not sure if this will help but I had the same issue with my 2002 TDi Sharan, I was convinced it was the immobiliser BUT it turned out to be the CAM sensor, I just happened to disconnect it and the car started although it took a few more turns than usual to start. I have now replaced the CAM sensor and it starts nay bother, I know you mentioned that there were no error codes it's something you could try easy just by unplugging the sensor and try to start it. On my Sharan there are two sensor connectors at the front of the engine block just behind a ball shape thingy, you will find two one is black and the other a gray connector, the CAM sensor is the one that leads to towards the timing chain cover towards the top, if I remember correctly it is the black connector. Give it a shot just in case. Regards