My Bosch Dishwasher leaks water into the pan which eventually is enough to activate the float in the pan and run the discharge pump constantly. I found out where its leaking from. The leak is from the vent hole in the top right corner of the water inlet system. It only leaks when the dishwasher is draining. First off let me assure you that the drain hose is not blocked, I took it right off and blasted hot water through it. The inlet to the kitchen disposal (garborator) is not blocked and my sink drain is not blocked. I have rigged up my dishwasher to run in the middle of the kitchen floor so I can see what its doing. I have attached a link to a picture of my water inlet system, hopefully the link works.
I am hoping to find someone who is familiar with this water inlet system (WIS) part. The WIS is basically a plastic manifold that has 3 hoses attached to it. One hose is a braided nylon hose that handles the incoming fresh water. The fresh water comes into the WIS through the hose and goes through a channel and into another part. The other 2 hoses are discharge hoses. One comes from the discharge pump and goes to the WIS, the other goes from the WIS and goes to the sink drain. So basically the discharge water flows through a horseshoe shaped passage in the WIS and out to the sink. In the WIS, above the hose connection that goes to the sink, there is a black thing and I dont know what it is or does. I'm guessing that its some kind of relief valve incase the discharge hose to the sink is blocked. When my dishwasher drains, discharge water goes through the horseshoe shaped passage in the WIS and into the drain hose to the sink but it also goes into this other passage with the black thing, through a passage along the top of the WIS and into the same passage as the fresh incoming water uses to go into the fill valve system. This is when water comes out of the vent hole in the top right corner of the WIS and drips into the pan under the dishwasher. If this black part is in fact a relief valve, I guess its stuck open. As you can see from the picture, mine has some crud in it. If I replace my Water Inlet System, will my problems be fixed? For now I have just put some duct tape over the hole so I can use my dishwasher.
Thanks for any help you can provide, Jon

Jon, did you ever get the leak in your dishwasher resolved? I have the exact problem and wondered how your situation ended up. Please let me know if you can. Thanks...

Found this issue in our case.
After changing the inlet water valve the dishwasher started leaking. Too much water was getting in.
We reduced the pressure of the water at pre diswashed faucet, open at 1/3 and it fixed the issue.