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Hi all,

My 2005 (D17A1) Civic LX keeps throwing the P0401 check light. I've changed the EGR valve twice (no new gasket though but no leaks either) The valves I changed were used but there is no way that all 3 of them are stuck or have failed because I cleaned them all before putting it on.

Also, I've soaked the passages with Carb Cleaner overnight. The cleaner just sat there and didn't seem to drain anywhere on both the intake and exhaust sides. So does that mean its clogged somewhere? The exhaust seems fine because when I rev the engine the liquid spurges out, leading me to think the intake is plugged.

I'd like to ask a few questions:
Is there a diagram with where all the EGR passages come from and lead to? Where is the intake manifold EGR port located and how do I clean it?
Do I need to take the valve covers off to clean the passages?
Is there any other suggestions you guys can make to help me clean the passages?

Thanks for your help! Sorry if this topic has been posted many times.

 
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gearbox

 
Rep Power: 811

well it sounds like the valve itself is not the problem but a clog somewhere else. you might try a bendable wire brush or pipe cleaner type of tool with carb cleaner to see if you can clear out the carbon deposits. they are very hard to get rid of without scrubbing. i do not have any diagram of the egr system ports unfortunately.

 
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Okay I'll try that. Where would I find one that fits? Could I clean the passages by taking of the intake manifold? Or is it all tunneled into the block?

 
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could try any cleaning aisle of supermarket. and i think the egr passages are going inside the head and block.

 
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I scrubbed as much as I can and as deep as I can got a lot of stuff out. But I've got a feeling the light will come back on again. I was just wondering how the ECU can tell there is insufficient flow? is there a sensor?

 
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Should be one on the egr I believe.

 
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Argg light came on again. Hmm well I scrubbed the egr and got any gunk that I could out and the passages I could only clean about 4 inches into the ports with my scrubs. I can't seem to find anything smaller and bendable that will fit in there.

Where is the Intake manifold port? Could I scrub at it if I took off the intake manifold? Is that hard to take off?

Is there any other suggestions?

 
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Yes, I'm having the sames issues. I got a code P0401 from Autozone. When I looked at my EGR Valve it was very rusty, so I replaced it with a new one. I cleaned out most of the black disposition where it was sitting as well. I'm still getting the check engine light. I'm thinking about cleaning the egr passages. Does anyone know how to do that?

 
Rep Power: 811

you can try carb cleaner, but alot of that carbon is burnt in and needs to be scraped off. maybe a wire brush but im not sure how far you can go with it. you might also need to wait a bit after installing the new one to give the computer enough time to realize it works again. also be sure and change the gasket. i reused the old one but many times it will leak and cause problems. if there is even a small leak, the engine light comes on.

 
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Thanks for the reply gearbox. As the weather warms up, I'm going to try and take of the intake manifold to clean the passages. Is there a guide for taking of the intake manifold?

Thanks.