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Discussion Starter · #1 ·
I have an 03. I live in Ca. and I have to smog my truck this month, and it won't pass because I have a cel on I have cleared the codes, and replaced parts for the codes but light keeps coming back on any sugestions the codes are P0101, AND P0404. I have replace the MAF sensor, a new EGR valve. I even replaced the regulating vent valve. any one that can help please
 

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First thing, welcome to the forum. Second, go to the user control panel and fill out your sig so we know what type of truck you have as well as any mods.
 

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By reading your post, I'd say to check your vacuum level to make sure you are getting 20" vacuum at the tee that feeds the vacuum regulator vent valve and the solenoid that controls the butterfly intake valve. Check all your vacuum lines and make sure they are intact and that the line coming up from the vacuum pump has not collapsed, the walls of with are pretty thin close to where it plugs into the pump. Is it indeed the vacuum regulator vent valve part number 1997254 that you replaced?
 

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Discussion Starter · #4 ·
First off thanks for answering. I will try to check the vacuum presurre as I have never done this before, are there any other possible causes, And yes that is the exact part # that I replaced.
 

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There are 2 solenoids in addition to that one. One controls the butterfly valve and the other is located between the EGR vacuum regulator sensor vent valve and the baro sensor and EGR valve. If either one of those are bad, it might also throw those codes although it is not common for those to go out. The part number on those is 94459951.
Not sure how to check their operation except when the engine is in normal op temp and at idle. You should be able to hook up a vacuum gauge after each one to see that they open. If you do a search, you'll find a schematic somewhere in this section with some pictures or search my user name and you can find it in some of my older posts. Good luck!
 

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Discussion Starter · #6 ·
Thanks for your help, I found the problem today and fixed it passed smog so we are good to go. It was a hose that comes out of the vacuum pump it was spliced, I replaced it and done no more codes. Once again thanks for your help.
 

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Discussion Starter · #7 ·
Now after a couple of days of being back to normal I got cel back on and now I get a
p2227 code. Any suggestions or any help would be greatly appreciated.
 
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