I watched the excellent video of how dishwashers work, cleaned the filters, moved the soap door around, did a test run - fail. I tested the electronics of the valve- it passed. I added water from a pitcher as suggested and isolated the issue to the valve. Ordered the <$30 part, installed it and did my first wash run. All seems to work, without any service calls.
Replacing the valve only requires a screwdriver, 2 wrenches, some teflon tape and pliers to open the tubing clasp. Small hands help too.