Yes, I think you're right on both accounts. The valve itself would be inside the aluminum block and virtually impossible for a lay person to test. There is a spool inside that shifts when voltage is applied to those coils that "hang off" the electric-side of the module. Coils set up a field that pulls the spool one way or another. The question then becomes "is the valve itself actually not shifting" or "is the valve shifting properly and the module just does not recognize it"?
Still don't know what software you are using, but suspect you are close to done unless you can build a test set-up to check the module. It becomes a matter of economics at some point. You will always have that question of is an input to the module not there or is it there and the module just can't sense it.