I believe it is the oil filler locking pin. Hard to tell for sure from the picture.

Wow, thanks for the reply! It's is exciting to finally start narrowing this down.

The next question: I can't find the oil filler locking pin location. I looked around the oil filler tube that is on the passenger side of the van, close to the dipstick. Is the filler you're suggesting on top of the engine, under the airbox and all that plastic?

Again, thanks for the reply,
Punk

I finally found the link to the part that I thought it was, but this doesn't look the same.
Tranny Cap mod - Sprinter-Forum
Not sure what you have there.

Originally Posted by punk

This was left below a wiper after an oil change at the local dealer.

Any idea what it is, a different dealer could not figure it out.

Thanks,
Punk

Is it the tool to open the oil filter