Yamaha DTXpress/DTXplorer/DTXtreme

OK, so the pad works and is wired correctly.  I think the most likely problem is that the pad type is not set up correctly in the trigger menu.

I am not familiar with the DTXpress IV menus (I have the DTXpress III) but I think you need to look at page 36/37 of the manual and set the trigger type for the pad to "PCY3".

I assume you know that to use the choking you need to grip (squeeze) the rim section of the cymbal after you have hit it?  It can take a bit more force than you might expect - not like a normal cymbal.

Keith.