If your dishes aren’t getting clean because wastewater keeps draining back into the dishwasher, the drain check valve may be broken. Order a replacement check valve with part #00611320 for most Bosch dishwasher models. Then unplug the appliance and follow these steps:
1. Open the drain sump.
Remove the bottom access panel by removing the screws on either side. Lift the panel away and set it aside.
Pry up the white locking collar that connects the drain hose to the sump. Then pull the end of it out of the sump. You can remove both of these parts by hand.
2. Remove the check valve.
The check valve is hooked into the inside of the sump by two locking tabs. In order to pull the part free, stick a small flathead screwdriver into the sump and push on the grooved edge to rotate the part counterclockwise. Once you hear the click of it pulling free of the locking tabs, you can reach in and remove the old part.
3. Install the new check valve.
Slide the check valve into the sump. Make sure the grooved edge is oriented outwards, with the triangular notch at the top. Press it into place by hand and listen for the click of the locking tabs snapping into place.
2. Reassemble the bottom of the dishwasher.
Push the end of the drain hose back into the sump until it’s fully in place. You should not be able to see the black ring anymore. Next, snap the locking collar back in place on top of the hose and sump. Make sure you don’t clip or pinch the wires next to the sump