I have a Bosch Dishwasher SHU9915UC/11 which has worked flawlessly for about 11 years.
After a long period of cleaning perfection, I recently noticed that I will occassionally get an imperfectly clean load of dishes. I am not sure if this is relevant to the problem I am not having but I mention it just in case.
The "problem" started last week when we ran the DW as usual and went about our business. About 4 hours later we noticed that the DW was still running. No unusual sounds or anything... just the usual washing sounds. Water was in the machine, spraying the dishes.
I am an ME and I did a bit of online research, disassembly and debugging and here is what I have found.
The usual dishwasher cycles will not work properly: they never terminate. As far as I can tell, the DW will run forever if I don't open the door.
I removed the control board and looked for any evidence of the common "relay overheating problem." No evidence of this at all. All I achieved here was break a snap tab on the control module which was so brittle that it broke when I looked at it.
I checked the current in the red heater wire with a current clamp and it reads 10A during the initial water heating cycle, which seems correct.
I tried running the diagnostic described on this website. I got up to the power scrub plus and wash lights flashing. but it wasn't clear what to do next. (Keep in mind I can not see the indicator lights if the DW is closed; my DW has controls on top edge only). So as far as this diagnostic goes, I did not learn anything new.
My DW has no display on it. That is, it is not able to display any error codes other than through the LED indicator lights.
I ran a rinse-hold cycle. I am familiar with this cycle so I know how it should sound. When it drains at the end, the drain pump keeps running and running even though the water has clearly drained. To me, this says float switch. But I don't see how this would cause it to run infinitely (with water actively spraying on dishes) during regular cycles.
Any advice? My next step would be to pull the DW out and take a look at the float switch area.