I think the primary concern is it will fail if the tech looks for it. We have a couple thingsd to our advantage 1) the EGR is quite difficult to see when you know where it is, But this doesn't stop a tech from checking is book if ge isn't sure. 2) These cars aren't all that common so the likely hood of the tech knowing there is supposed to be one and taking the time to look for it is rare, but not impossible.