Hi there,
I've had several messages on my Diplomat dishwasher over the 12 years I've owned it, E1, E7, you name it and in both cases, it is down to the unit not emptying due to either:
a faulty drain pump or
a blockage somewhere
To clear the blockage, the best thing I've found is a hose through the kitchen window and to spray water into various orifices of the unit! Obviously, you can only do this for so long untill the unit fills up. You then have to empty it with some kind of pipe (I used a length of normal garden hose) and start again until you get clear water. I've also spilt salt into the unit when filling the salt reservoir, and thought it would just wash away. Don't make this mistake because I've just had to go through the entire unblocking process to clean this out. Am sitting here with crossed fingers as we speak, hoping I won't hear that dreaded beep.
I've had to do this 3 times in the past so would agree with the previous comment that generally, the unit is OK. The drain pump, touch wood, seems OK.
Don't give up - I've had a situation where after a clean-out, the washer goes for up to 15 minutes and then beeps. You just need to get the hose out again and keep plugging on.
Hope this helps.
Thanks
Tony (NOT a plumber), December 2008