Rep Power: 0

Okay so my civic has a D17A2 engine. The check engine light keeps coming back on saying P0401 (EGR flow insufficient).. Now it seems like an easy fix, just clean out the EGR system, right? Nope... First of all, the cylinder head is completely clean, I just had it machined and everything two months ago. Second, I took the Intake manifold off and the EGR ports were already clean, absolutly no carbon deposits or anything, but I cleaned the ports anyway, and put everything back together. Next, I took the EGR valve off and cleaned it with Carburetor Cleaner. Still the check engine light came on. Here is where it gets weird... I confirmed that the EGR valve itself was work by manually operating it with a jump box, some wire, and alligator clips. When I powered the valve, I could indeed hear it closing and opening, so the EGR valve itself is not the problem.. Then, I cranked the car, and manually opened the EGR valve, and the car did not stall, as it should.. Because the car did not stall when the valve was fully opened, that means there must be a blockage somewhere, but the ports are all clean and the EGR valve is work properly as well. Does anyone have any idea where I could go from here?

 
Rep Power: 518

I bet you have the wrong gasket on it (between the injector plate and the head).
I think the gasket for an 01-03 LX/DX has no hole for the EGR passage.

 
Rep Power: 0

change the egr valve and make sure you have the right gasket like ezone said. just because you hear it working doesn't mean that its opening, they strip out.