There's a bit of Confused in this thread.. although I've only skimmed it, so it may just be me.
First of all, the simple stuff.
If you *remove* your EGR and blank off the entry/exit ports, you will get an error when the ECU doesn't receive a response from the EGR.
You can get some tweaking done to the ECU so it doesn't check the EGR is responding (to prevent the "EGR missing" error...) but there's no point. Leave your EGR in place and pocket the €150, less my commision €50 for the money I saved you..
You won't get an error just because you blanked off the EGR. It only checks that the EGR is alive and working through its open-closed movement range... it doesn't measure gas flow through it etc.
The blanking plate with the holes in it is a retro-fit, which is why it appears to have been tampered with before.
Fiat introduced the mod' to try and get some "swirl" in the exhaust gas so that it prevented a bit of coking up, so it's a pukka factory mod' (though also copied in the aftermarket).
On the other hand... it doesn't 100% work as you have found out... so dump the plate with the holes in it.
You should just clean your EGR to buggeration. There's a cylinder that moves and it's that which gets bunged up. The EGR may still be good, if it's cleaned and freed up to move... or it may be burnt out from fighting a resistance... but you have a new one now, so it's too late to worry about that now.
Once you have a new/cleaned to buggeration EGR you need to make sure it doesn't get clogged up again.
For me, the *only* sensible way to do this (and I'm not interested in any further debate..
) is to blank both the EGR entry and the exit ports.
The best place to blank the exit port is immediately next to the EGR valve. It's the best place because there's no other place to close this off.
If you don't close off the exit, oil mist and gum from the inlet manifold will find its way into the EGR and accumulate around the mechanism, since there's no positive pressure/exhaust coming from the EGR side to prevent it.
Your EGR will get gummed up rather than sooted up (appreciating that this will take a while) but you'll get another error, eventually.
The other (and main) place to blank it is the entry port.
The best place to do this is at the exhaust manifold where the EGR plumbery joins the exhaust system. This will prevent gas/soot being deposited inside the metal pipe that runs under the inlet manifold to the EGR. If that pipe gets blocked up it's no big deal but if you ever want to ressurect the EGR (if emissions tests/testing changes) then you don't want a pipe full of coal.
But as these nuts are likely to be crusted to the manifold, you won't be able to undo the pipe at the bottom, so the other place to do it is at the top, next to the EGR itself, which is doubly handy since you already have to remove the EGR to fit the exit blank anyway.
So... in reality you'll end up with two blanks, right next to the EGR entry and exit ports, respectively.
The last thing.. buy stainless 2-3mm blanks from the internet. Don't do all this work/cash and then DIY some old Coke cans or they'll fracture/melt and you'll have to do it all over again. Check whether your motore is 120bhp, 115bhp or 85 etc... and get the blanks for that engine, since the hole spacing is slightly out (you'll see some blanks have slotted holes, to make them more universal. They work too,).
This way, your EGR will be working fine but will be protected forever in a nice soot/grime free chamber.. Keep it plugged in... it'll be doing its thing but obviously no gas will be bothering it so it'll stay clean/functioning forever.
Ralf S.