Miele G653SCV1 D/W not finishing cycle

Hi, this machine isn’t finishing off its cycle. Its not pumping out at the end. Theres a tube which comes from the pump onto the housing underneath the bottom spray arm that you can take off and get to the drain pump impellor. When you take this off and put it back on again, it goes through a cyle ok. Then it will always stop on the next cycle. Can get stuck at the start or the end of the cycle. Any help please?