if EGR cooler is restricted you would get that code , a test i like to do is bring up in live data MAF g/s and EGR data,

look at the MAF and the % EGR at idle , the transporters i use this test on will command 60 to 70 % EGR at idle for a few mins before they go to 0

when its at 60% or so operate the EGR cooler Bypass valve (The vacuum operated black plastic actuator on the top) and see if the MAF g/s goes down by a significant amount, .
if it does it shows that the cooler is restricted.

this test will not work on vehicles that do not command EGR at idle and i am not sure how good it would be at higher RPM's as i have not tried it.