No water in dishwasher

I have a Bosch Dishwasher SHU9915. No water will enter the dishwasher I have replaced the water valve and still no luck. What is the next step. There are no water flow issues.
I have an older Bosch, a SMU4052 model. It's been for 13 years, but has stopped taking in water. I think this was a gradual problem as we did notice in the past month that it wasn't cleaning as well. A very small amount of water is coming thru, but neglible now. The copper pipe leading from the valve into the dishwasher is not getting hot, so I'm wondering if the problem is right at the valve. The pipe before the valve does get hot when I run the hot water in the sink. The valve is in a place where the pipe forms a sharp elbow. Should we replace the valve? Or if it's a buildup of sediment, is there an easy way to clear it? I also checked the pipe where it enters the dishwasher at the bottom front and it is also cold to the touch.