The E15 Bosch error message is related to a feature of the dishwasher to prevent it from flooding. So if the pump fails or something, rather than spilling water all over your kitchen floor, it basically shuts down. While researching the Bosch E15 error message, I found lots of different reasons for this message. Some of which are simply that the dishwasher is dirty and that filters inside it should be cleaned out. That wasn’t my situation. Some will say, pull the dishwasher out, angle it at 45 degrees to drain excess water out of the machine. While that will “work,” it doesn’t solve the underlying problem that is causing the dishwasher to go into E15 flood mode.
In my case, the issue appears to have been related to how the dishwasher was installed. The dishwasher drain hose has to wind its way through my cupboards to get to the sink drain. In doing so, the drain hose ran all the way up to the underside of the countertop, then dropped back down to get to the drain. That huge arc was apparently way too much for the little pump in the Bosch dishwasher.
I didn’t install the dishwasher, it was here when I bought the house a few months ago. So I pulled everything apart and rerouted the hose to go pretty much straight over to the drain and eliminated the big arc. I’ve been running it for about a week without any E15 error messages.
So if you get an E15 error message on your Bosch, check your hoses. I don’t know this for a fact, but I’d keep the hose running below where it hooks up to the drain. And I’d certainly avoid huge arcs in the hose. While it did run fine for quite awhile with my old hose setup, my guess is that the pump isn’t as strong as it was when it was new, and it couldn’t push the water over that hump, and so it was backfilling into to the machine and causing the E15 Bosch error.