If everything checks good out fine for Error Code 9-4 then I'd next check the door vent. Your model has the problematic door vent that causes random errors to show up and not complete a full wash cycle.
Do this first--->Disconnect all the wire connectors to your door vent and see if it runs through a complete cycle.
Start reading what bigbuck said at post#18 here:
So after successfully running the one hour cycle with the vent wire harness disconnected, I ran the ProWash/ProDry cycle with the vent harness disconnected with 100% success.
www.applianceblog.com
Your model uses the exact same door vent. If it runs through a complete cycle and everything is back to normal, then order and replace the door vent assembly.
Here it is for your model you can order:
WPW10469574 Vent
To access the vent assembly you will need a T-15 torx screwdriver: Remove 4 screws (long) across top of door, then remove 10 screws (short) on the sides, then the outer door panel pulls off.
Let us know what you find.
Jake