# 1996 Sentra Error Code p0400



## Allysen7278 (Nov 17, 2009)

Engine Light Came On so I went to Advanced Auto and got diagnostic when p0400 came up. I was wondering the cost to repair such a problem and how long can u prolong fixing it before it does damage to the engine??? Please HELP


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## Jdoggsc (Dec 25, 2007)

P0400 is EGR malfunction. here's a PDF of the factory service manual pages for P0400 do what you can to find the problem and you'll save yourself a lot of money.

EGR just does *E*xhause *G*as *R*ecirculation to improve emissions. it isn't really critical for engine function, but will throw an error if it's not working right because it affects emissions. 

As far as I know, it won't actually damage the engine. Correct me if i'm wrong, anyone.


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## davidtemple (Aug 11, 2010)

Thanks so much now I have to go locate the egr


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## PTXer (Aug 31, 2006)

Follow the small steel tube that comes out of the exhaust manifold and bends around to the backside of the motor. Usually there is a short small diameter rubber tube coming out of the EGR that gets clogged and becomes crumbly. You can take the EGR off and inspect to see if the diaphram moves with vacuum. The little hose is probably it.


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## slavrenz (Apr 16, 2010)

PTXer said:


> Follow the small steel tube that comes out of the exhaust manifold and bends around to the backside of the motor. Usually there is a short small diameter rubber tube coming out of the EGR that gets clogged and becomes crumbly. You can take the EGR off and inspect to see if the diaphram moves with vacuum. The little hose is probably it.


+1. That was the problem for me.


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## azkicker0027 (May 31, 2002)

i had an EGR problem as well and it turned out to be one of the vacuum lines became too brittle and leaked the applied vacuum to open the valve. 

see if you can manually activate the valve with a vacuum pump. it should stall the engine when you apply vacuum at idle.


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## Jopet (Aug 10, 2009)

does anyone know what size of the hose that is connected at the bottom of the egr valve and goes to the bottom of the solenoid? We replaced that hose with whatever we had at the time and I think somehow its leaking.


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## lukesSX (Feb 17, 2010)

I'm not sure what size it is, but I don't think you can't use any old hose or else it will deteriorate.


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## Jopet (Aug 10, 2009)

Its 1/4 in. and I found one in an autozone for about $3 2feet of hose. Its a fuel/exhaust hose. I dont know why I didnt fix this sooner (laziness is costly). 15 minute to replace (including cleaning of the air intake and maf with maf cleaner) 
It seemed to fixed my mpg issues. But I still have to run a few miles to be sure.


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