On the non-turbo 606, which I believe has a similar EGR system, I removed the flap in the EGR body and disconnected all the vacuum connections. The flap in mine was attached to its axle by a pair of Phillips screws; I think this part was easier with the EGR body removed from the engine. The idle state of the EGR is zero exhaust recirc, so with no vacuum anywhere the exhaust valve should stay closed all the time.

I actually went so far as to remove all EGR vacuum tubing all the way back to the vac pump, because none of it serves any other purpose. Check the vacuum diagram for your engine to see if that's the case in the turbo as well.

If your state's inspection doesn't require emissions test for diesels, you can block the EGR port on the exhaust manifold and remove the whole thing, EGR body, valve, and vacuum actuators, and replace the EGR body with a rubber coupler or some intake tubing. Saves a little weight, reduces intake turbulence, and removes some unnecessary clutter from your engine bay.

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RIP:
2011 E350 BlueTEC, Schwartz 81k (totaled by uninsured drunk driver)
1964 Unimog 404.1 (wrongfully towed by the city)
1994 E320, Brilliantsilber 208k (transmission shuffled off after sudden catastrophic fluid loss)
1982 300D, Silberblau under a blue repaint 256k (sold for parts)
1995 E320 Polarweiss, 131k (sold for parts)
1995 E300D Polarweiss, 287k (totaled by drunk driver)