BadBob Posted September 3, 2008 Share Posted September 3, 2008 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? Quote Link to comment Share on other sites More sharing options...
bobs91ls400 Posted September 4, 2008 Share Posted September 4, 2008 Did you clean out your vacuum lines? Debris from bad parts clogs the lines. Quote Link to comment Share on other sites More sharing options...
UCF3 Posted September 5, 2008 Share Posted September 5, 2008 I'd replace the ERG Modulator. Sometimes debris gets stuck in there and you can't get it out. Quote Link to comment Share on other sites More sharing options...
jbarhorst2 Posted September 6, 2008 Share Posted September 6, 2008 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 Quote Link to comment Share on other sites More sharing options...
lbaskball45 Posted September 7, 2008 Share Posted September 7, 2008 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. Quote Link to comment Share on other sites More sharing options...
1992LexusOwner Posted September 24, 2008 Share Posted September 24, 2008 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 Quote Link to comment Share on other sites More sharing options...
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