I had a problem with my Siemens dishwasher(SL65M350GB) whereby it wouldn't drain. After emptying the water in the bottom of the washer manually I took apart the bottom filters in the bottom of the dishwasher unscrewed the pump cover and got to the impeller where I found a rubber band wrapped round.
After clearing this band from the impeller as soon as I switch the power on to the dishwasher the pump runs all the time even with the door open and with no water to drain.
The washer then doesn't get past this it just keeps running in this mode.
I tried filling the bottom of the dishwasher with some water but this which then drained but the pump kept on running and didn't make any difference.