Just had another idea, I would like to run by your egr consultants:

Instead of disconnecting on the exhaust side, try this. Just disconnect the intake joint, make either an aluminum or stainless plate for that port and bolt the egr right back over it. The bolts are plenty long and that will close system. However, since the exhaust port is still open, the pressure will open the egr valve, although no gas will flow (except perhaps a smidge will flow up the egr shaft and thus escape--should be minor). Since it is the upward thrust of the valve, that triggers the sensor(not air flow), that should satisfy the computer that the system is working.
Any comments will be appreciated. Harvey

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hlg