Defy Dishmaid Dishwasher (12 place), 2 yea...

Well, I fixed it in my case, by opening it up and taking a look. It seems that water was leaking out of the main compartment into the guts of the machine and shorting out a solenoid (I think). In my case, the water was leaking at the location where the 'water hardness adjustment' knob/screw is. This is in the middle of the left inside wall. (Take a look at your manual)
This may or may not be the problem in your cases, but it certainly produced the same symptoms. You need to be somewhat technically inclined to do this, and ABOVE ALL, make sure the dishwasher is off, unplugged and the water supply is turned off before going any further...
You start by taking off the top 'preparation surface' o the dishwasher by lifting two plastic clips at the back of the machine and sliding the top backwards and off. Next, by removing the left cover plate of the dishwasher (there are screws at the back, top and front of the machine), you expose a large flatish plastic device about 150x300x15mm that is responsible for dividing up the incoming water to add salt to one portion and then presumably recombine the water. This is held in place by two clips on the left side and the large ring around the water hardness adjustment screw on the inside of the machine. Twist off the ring and give the plastic thing a good pull to loosen it from the black tar-like stuff. Once it is free, you'll see a black o-ring that seals the joint between the plastic device and the main compartment. In my case, this was full of gunk and not sealing properly. I gave it a good clean and refitted the whole assembly. For good measure I also checked the clips securing the hoses connecting to the plastic device and made sure they were sound.
There is an electrical connection to what I think is a solenoid below the plastic device described above at the bottom of the machine. In my case, water was dripping down on top of the electrics when the machine took in water and I guess must have shorted out the solenoid, bringing the whole water delivery process to a halt. This created the mpression that the machine would fill up with water and go no further. I gave the whole area a good dry with a cloth. I also had to tilt the whole machine and allow the water that had, over the last few days acumulated inside, to drain out. 
When everything was dry, I put back the cover plate, plugged the machine in and turned the water on and tested with a rinse, then a number 3 wash another three times. Everything worked fine.
Please be very careful when working with machines like this. Electricity and water don't really mix. I advise if you are not qualified that you ask a suitably qualified person to do the job for you.
Good luck.