Egr Valve

[BadBob]

Check engine light came on. Checked with my OBD scanner & one code PO401 appeared - egr valve. Bot & installed new egr valve, cleaned out little cotton filter in the egr vacuum modulator, replaced charcoal cannister. Ran great & no check engine light for about 8 days but then the check engine light - PO401 code egr valve reappeared. Any ideas?

[bobs91ls400]

Did you clean out your vacuum lines? Debris from bad parts clogs the lines.

[UCF3]

I'd replace the ERG Modulator. Sometimes debris gets stuck in there and you can't get it out.

[jbarhorst2]

Here's another suggestion as well. Could be that the exhaust passages on the way to the EGR valve are partially plugged and not letting enough gas through. That was the problem on my car. Once cleaned out it was fixed. I also had tried replacing the EGR temp sensor, to no avail.

Tom

[lbaskball45]

Heres couple of easy steps to try:

Get a vacuum pump, plug the end to the egr valve, and pump it and see if it holds vacuum. If it doesnt hold vacuum, you may have replaced with another ruptured EGR valve. Clean the lines as people stated before. Lot of carbon gets built up. Lastly, check the EGR temp sensor. If that is bad, EGR may not function properly as well. Check for proper resistance. Common issues are the modulator going bad, the EGR diaphgram rupturing and/or carbon build up in the vacuum lines.

[1992LexusOwner]

I have done some research on the EGR, and you may want to consider deleting the whole thing. Heres the link for it.. Hope this helps you out. http://www.lextreme.com/egr.html