Bosch makes pretty tough drain pumps. I've replaced one in my whole time and I probably didn't need to do that one. Put a good amount of water in the dishwasher, get a pail, disconnect your drain hose from the disposal, and hit cancel-drain. If you have a good a solid stream of water, the pump is fine. If you have a pulsing flow or a trickle, you might have a drain pump issue, or more probably a blocked hose.
The heater and the wash pump are integrated together. This is a tough replacement. You have to completely dismount the dishwasher, put it on its back, take the bottom off and get to the main motor that way. There is a LOT of stuff you can break doing this. Because I do those so rarely, I budget 3 hours for this job. (Waiting for Samurai and Durham to blow raspberries at me for taking so long.)