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Anthony, Chevy Technician
Category: Chevy
Satisfied Customers: 11751
Experience:  GM Certified
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Chevy Venture: P0401..I replaced the EGR valve, but the failure

Customer Question

Hello, I am getting a P0401 code (99 Chevy Venture). I replaced the EGR valve, but the failure returns after some driving. HELP !!!!
Submitted: 6 years ago.
Category: Chevy
Expert:  Anthony replied 6 years ago.

Hello! Welcome to justanswer!


It wasn't the valve but it is the parts being clogged. Take off the valve and clear out the holes going to it. Use wire and you will see that the one going to the intake is blocked with carbon. See it all the time.

Anthony and 6 other Chevy Specialists are ready to help you
Customer: replied 6 years ago.
Sorry. I'm finding it a little awkward to navigate around here. I have typed you a couple follow-ups to this case but am unsure as to whether or not anything was sent to you. Thx. -Steve
Expert:  Anthony replied 6 years ago.



I didn't get a follow up. Try replying here...

Customer: replied 6 years ago.
Hey Anthony. Thanks for getting back to me. I am not likely going to be able to get around to actually taking a look at the Venture for another day or so. You'd recommended that I use a wire to clean out the carbon build-up. For starters, is there a particular kind of wire I should use? Also, the opening is pretty large. Would the build-up you're referring to be where the EGR valve mounts or further down in the hose/tube? Thx. -Steve
Expert:  Anthony replied 6 years ago.
Just use a piece of mechanics wire and carb spray. The port that goes to the intake is the one that clogs. Let me know how you make out.
Customer: replied 6 years ago.
Makes sense. I'm assuming that even a partial blockage can cause this problem, and we're only talking about an inch or so of area, correct? I hope to get a chance to try it today. I have to work outside because the garage is currently NOT a garage ;) I'll definitely keep you posted.
Expert:  Anthony replied 6 years ago.

Good morning!


Please do keep me posted...

Customer: replied 6 years ago.
Good Morning, Anthony!

Well, I was able to give the intake port a good cleaning before the sun set on me yesterday. (I knew that I couldn't leave it alone until today - ha.) I did manage to remove a significant amount of crud. Unfortunately, NOW I have (2) fault codes: P0401 and P0171 (Bank 1 Too Lean ..). Did I mention that not only am I not a mechanic but I have the worst luck too?
I'm assuming there could be a vacuum leak (caused by me, perhaps?) or the MAF could need to be replaced/cleaned? Any suggestions/ideas? If it ends up being a big job (intake gasket, etc ...), I believe it's time to send "Marcy" to pasture :) I will be in and out today, checking my messages periodically. Please respond when it's convenient. I hope that I can get a chance to jump back on this, um, 'project' in a few hours. Thanks again for all your help! -Steve
Expert:  Anthony replied 6 years ago.



Go over it again and be sure to replace the throttle body gasket if you took the throttle apart and make sure you have no vacuum leaks. Then clear the codes and see what comes back.

Customer: replied 6 years ago.
Thanks for the response. I did not take the throttle apart. I will re-trace my steps and let you know how it goes. S
Expert:  Anthony replied 6 years ago.
Please do.
Customer: replied 6 years ago.
Hi Anthony,

I went back through and checked everything, removing and re-installing the EGR valve. I am at a total loss now. The only additional thing I did was disconnect and reconnect the MAF. (Why? Because it was there!) Since P0171 can be linked to MAF, then I suppose there is a chance that could've caused the code. I find that strange, though. I literally just disconnected and reconnected the MAF connector. ?????
Any suggestions? Could I have damaged something when cleaning the intake port?

Expert:  Anthony replied 6 years ago.
Ok, is the only code now the 171?
Customer: replied 6 years ago.
No, the original code is still failing as well. Both 401 and 171 codes are now kicking-out. I'm afraid to touch that van anymore - ha.
Expert:  Anthony replied 6 years ago.

Ok, at this point you need a better scan tool hooked up to be sure the computer is able to open the valve. YOur scanner cant do that. Theres a chance that the computer is not powering up the valve when it should be. New Valve and clean ports point to a bad computer. Have it tested first. Dont replace anything else. Handle the 170 after you clear the EGR code...

Customer: replied 6 years ago.
That makes sense. (Scary - ha) I really appreciate the help. (In a sick way, I'm actually enjoying this, plus I'm LEARNING some stuff.) I know that a new computer is going to cost more money than I care to sink into the ol' girl. However, I "know a guy" who might be able find locate a used one if it comes to that. Do you mind if I contact you once I've had a chance to look into this further? I'm going to make some calls and see if I can have this checked sometime this week. The license plate and inspection ran out back in June. (I know. This has been an "on again/off again" project. I was hoping to either get the Venture back on the road as a 'hauler' or pass it on to someone else. Regardless, I need to do "something". The time has come. I haven't given-up on getting to the bottom of this.

btw, Thanks again!
Customer: replied 6 years ago.
Oh. Actually, replacing the engine computer (ECM, PCM, whatever it's called) does not look like the huge undertaking I was thinking it was going to be. (What did we do before computers?) eBay has some decent-priced ones, and I even know how to get to the thing (I think). Well, first things first. I need to have it tested first. I doubt that the local auto parts store will have the scanner needed to test the computer, huh? I will call around some shops tomorrow and see if someone can test it for me. Thanks again, and have a great evening!
Expert:  Anthony replied 6 years ago.
Your very welcome and I hope it works out for you.