P0401, EGR insufficient flow intermittent.

Friend's car is throwing this code. Checked all vacuum lines, applied vacuum to EGR valve, moved really smoothly (New valve). MAF specified is considerably lower than actual at idle, they match more once the EGR solenoid closes. I assume this just confirms that there isn't enough exhaust going into the intake.

The EGR cooler looked icky, I just pulled off the one elbow and looked. I didn't think it was totally clogged but could that be it?

It could be clogged enough. If you remove the pipes from both ends of the EGR cooler you can rod the tubes out with a coat hanger wire. You can get to most of them. Then, blow all the crap out with DusOff or compressed air. Be careful with the coathanger wire, you don't want to puncture a tube. If you do, you will have a coolant leak into the intake or exhaust system.

--Nate

PDJetta said:

It could be clogged enough. If you remove the pipes from both ends of the EGR cooler you can rod the tubes out with a coat hanger wire. You can get to most of them. Then, blow all the crap out with DusOff or compressed air. Be careful with the coathanger wire, you don't want to puncture a tube. If you do, you will have a coolant leak into the intake or exhaust system.

--Nate

Click to expand...

Weed wacker line would be a safer alternative.

Thanks for the tip, I'll do that the next time he's over. What are the tubes made out of? I assume the internals are aluminum? It's not like they're that fragile, are they?

They are stainless steel, as is the outter body of the EGR cooler, so they are probably pretty tough, so it may not be an issue. Just don't go hog wild and be concious of the fact that a puncture will cause a coolant leak. I rodded out the EGR cooler in my mother's '00 TDI several years ago and it was not a problem. Used a coathanger wire.

I was thinking that an even better idea would be to use a small bore gun barrel brush (the copper or nylon bristle type) soaked in gum cutter/carburettor cleaner. Use a short rod on the brush.

--Nate

I was thinking the same thing with the bore brush, hahaha.