i just worked on my friends 04 and it had a throttle plate in the intake manifold, it is a later 04 not sure on the build date but it doesn't have an 03 turbo. i was also wondering what it does, i have never seen another diesel with anything in the manifold. i guess it would work good as an air shut off valveThere is a throttle plate in the intake manifold. I don't know if removing it will trigger a check engine light, but I do know it was deleted by the time they started making 2004 models.
There isn't a butterfly valve in the exhaust like the 7.3L had.