What's it supposed to look like? I dug around in the back of mine pretty extensively when I was hunting for my TPMS controller, so I might have stumbled across this one at some point.
EDIT: I went back through the pics on my phone, and I think it's under the cubby in the back of the hatch on the passenger side. If you pull out the hard plastic cubby liner, there should be a slotted foam mold that houses a few different modules. PDC should be one of them.
In the pic below, it is one the right side where the small net is. Pull out the plastic piece behind the net and you should find the module.
