Dreaded EGR P0401 fault code... can't find what's wrong

Hi, so I got the dreaded P0401 fault code. But can't find the problem.

Judging from this readings (block 3), seems there is an obstruction on the flow.


I took a look at the EGR valve (disengaging the large black hose, etc.); a bit greasy inside but nothing else. While not a comprehensive inspection, seems diagram/solenoids are working just fine.

What may be wrong? Tempted to fully uninstall/clean the EGR valve (as I did 50k miles ago) but since it's PITA, I'd rather hear a second opinion.

Thank you for your input.

Anyone? thanks.

I would try cleaning it again.


you might get another 50k

meerschm said:

I would try cleaning it again.


you might get another 50k

Click to expand...

Trying that before this coming weekend. Will return with results. Thanks.

Observe the values as you run a basic settings exercise in block 003. You may also remove the EGR valve from the back side of the manifold, lay it atop the the motor while still connected electrically and output test the valve to determine if it is responding to control.

Any suggestions? So I had the EGR removed and cleaned. Warmed engine and plugged VCDS cable. No change on Block 3 . This are the readings:



These are other readings I got from running some tests:





Thanks!!

Looks like it’s responding to command in BS003 though I can’t really remember if those are plausible absolute values. Is the throttle valve working? What happens when you clear the fault? Does it come back right away?