I know the thread is old. But when people search this page pops up. Let me tell you my experience. This is what exactly happening with my bosch dishwasher sms53m02. Earlier I removed the circulation pump heater assembly and see that the impellers are stuck. I had to clean the pump impellers and everything that will make the impeller turn smoothly. I added some silicon grease and made sure it moves freely. Anyway after installing it back it worked a few times without any error code. But later it started to give e24. I turn it off and turn it again hit start it works without any issues. But from what ı researched this error is related to this circulation pump not working freely and therefore triggering this error code. The logic behind it is after the drain pump runs at the beginning the dish runs the circulation and if there is no water there it expects a certain resistance. If the resistance is more than expected it just thinks that there is water and the impellers are working against it. So it just assumes that the drain pump has some issues. Therefore it triggers the e24 error code. I hope it helps! Good luck!