GE Dishwasher Model No. GSD3200G00WW has standing water in bottom. Cycle appears to run fine. We even hear disposal sounding as if some water getting through. No blockage in lines. Opened plastic filter at bottom - nothing in drain hole blocking but full of water up past electric coils. If you have a part to replace - let me know where it is and how to get to it. 
I’m sorry that your question wasn’t answered on time. Although, it’s probably too late to help you, I’m posting the answer anyway, so that it may help other people with a similar problem.
The first thing I would do in such situation is check the piston valve (#564 at the diagram) condition and operation. You have to remove four screws holding the filter frame (#543) to access the piston & nut. To remove the piston valve you have to unscrew it CCW. Make sure the cone is in good shape, it goes freely up & down and, in the upper position, it closes the top hole. If anything seems to be wrong, replace it.
- The piston & nut assembly AP2617344
Here are the breakdown diagrams and Replacement parts for General Electric GSD3200G00WW Dishwasher | AppliancePartsPros.com
Gene.