Chosen Solution

New dishwasher is installed and working great. Still no clarity on what the issue with the old one is.

You have appliance gremlins.

The flood switch is tripped. This is located under the unit. Unplug or flip the breaker to the dishwasher, take off the black kick plate under the door, 2 screws, and you will see the white plastic “pan”. The flood switch is located where you can’t really see it but it is on the left hand side wall and is made of styrofoam. The best thing to do is to put some rags in the pan, this is not easy because there is little room to put them, and soak-up the water that has filled the pan. Eventually you will get enough water out that the float will deactivate the switch. What you hear “running” when you turn it on is actually the drain pump, it get activated when the flood switch is tripped.

When a Bosch is in error, it doesn’t matter if the door is open or closed. Before doing any voltage readings, check the voltage at the junction box where it connects to the dishwasher. Check the voltage and polarity. It could be a floating neutral/ground issue. If the polarity is incorrect, voltage readings at switch’s will be incorrect. Checking ohms verses voltage on a door switch would both have the same results. The switch is either open or closed no matter how you test it. The E6 error, as mayer said, relates to water issue. The noise you described on the left side is also where the fill valve is located. There is a water sensor in the housing on the left side of dishwasher. I have found the housing to have a build up of sediment in it and this will create the same issues you have mentioned. Replacing it solved the problem. To be continued Attached is a link on eBay. The water inlet parts #00499500 water lever sensor and #oo263833 water inlet, this is where I’d start troubleshooting if I was in front of the dishwasher. Turn power off to d/w. Pull unit out to gain access to the left side. Check ohms of each switch. Remove the wires from the switch before checking ohms to get accurate reading. Switch is either open or close depending how it’s used in the circuit. I hope something here helps you locate the issue. https://rover.ebay.com/rover/0/0/0?mpre=…