help! Ses light came on code p0400!!
Thread Starter
Joined: Jul 2005
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From: Ft. Wayne, IN
help! Ses light came on code p0400!! Hey guys was driving my car today and the ses light came on, so I hooked up my scanner and found dtc p0400. Which means egr flow fault! So does this mean my egr is junked or should I check the gasket between the header and the egr pipe. If it is bad, im going to just buy a block off plate. Hell all of the other emissions are deleted on the car anyways. Thanks!
Thread Starter
Joined: Jul 2005
Posts: 5,897
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From: Ft. Wayne, IN
Yea I was reding that at one time there was a recall on the obd-11 lt-1 egr system. The valve is too sensitive or something like that. I drove it 25mi today and it did not come back on.
Thread Starter
Joined: Jul 2005
Posts: 5,897
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From: Ft. Wayne, IN
Well the ses light came back on today. It threw the same po400 code. So I replaced the egr and it seems to be runnin alot better part throttle. Also the egr pipe is leakink were it connects to the header and I cant get the fuking thing to seal. The gasket that comes from pacesetter is worthless. Im gonna try using hi-temp rtv and see what happens.
that code sets because the pcm doesnt see the change in manifold vacuum that it expects from the egr opening. that can be many things. egr tube blocked, egr valve stuck, egr vacuum line broken, etc.
best this is to let the engine run and stick your hand back there (be careful it can be hot) and manually push the diaphram to open the valve. if the rpms drop and the engine wants to stall you know its the egr control system thats the problem, not the valve itself.
if the valve is working bypass the solenoid and take the vacuum line off the top of the valve and check to see if theres vacuum on that end. if not you've got a hole or restriction or the line simply isnt hooked up to either the solenoid or the intake.
if you go through all this and all is still good you've got either an egr solenoid problem or pcm problem. im not sure what you can do without a good scanner, but if you can get someone with a scan tool and have the pcm actuate the egr and see what happens. if it doesnt actuate you've got an electrical problem and might have to take it somewhere. if you've got a multimeter i could probably walk you through what you can check, but it more than likely wont get that far, you should find the problem before you have to worry about solenoids or pcms to replace.
best this is to let the engine run and stick your hand back there (be careful it can be hot) and manually push the diaphram to open the valve. if the rpms drop and the engine wants to stall you know its the egr control system thats the problem, not the valve itself.
if the valve is working bypass the solenoid and take the vacuum line off the top of the valve and check to see if theres vacuum on that end. if not you've got a hole or restriction or the line simply isnt hooked up to either the solenoid or the intake.
if you go through all this and all is still good you've got either an egr solenoid problem or pcm problem. im not sure what you can do without a good scanner, but if you can get someone with a scan tool and have the pcm actuate the egr and see what happens. if it doesnt actuate you've got an electrical problem and might have to take it somewhere. if you've got a multimeter i could probably walk you through what you can check, but it more than likely wont get that far, you should find the problem before you have to worry about solenoids or pcms to replace.
Last edited by noriceinside; Jun 1, 2008 at 10:54 PM.
Thread Starter
Joined: Jul 2005
Posts: 5,897
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From: Ft. Wayne, IN
well it's not the valve cause the ses light just come back on(after installing new valve). I got the egr pipe/header connection sealed up and the still the ses light is on. I also dont have any vacum leaks it's pullin 18in of vacum at 925rpm.
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well thats not what to check. check the vacuum lines coming from the side of the intake to the solenoid and then from the solenoid to the valve.
the line from the solenoid to the valve might be leaking and wouldnt indicate lower vacuum when testing at the manifold.
the line from the solenoid to the valve might be leaking and wouldnt indicate lower vacuum when testing at the manifold.
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Verdad Gallardo Thread Starter
Joined: Jul 2005
Posts: 5,897
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From: Ft. Wayne, IN
the vacum lines are good, my vacum guage in my car is tee'd in with the main vacum line that feeds the egr solenoid. I just started it up and disconnected the line that connects to the valve and there is no vacum.
of course there isnt vacuum. my bad i forgot to mention you'd have to bypass the solenoid. take some regular bulk vacuum line and hook it up from the intake straight to the valve. you engine should run like ****. unplug that line and it should close.
just a thought, the extra line for your gauge could be causing your egr to get a limited amount of vacuum, at least not enough to pull the valve open.
just a thought, the extra line for your gauge could be causing your egr to get a limited amount of vacuum, at least not enough to pull the valve open.
Thread Starter
Joined: Jul 2005
Posts: 5,897
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From: Ft. Wayne, IN
well it's been this way for 4yrs and no codes till now, also the solenoid pulls the vacum first and the guage is tee'd in after. IDK this problem has just randomly started and nothing has been touched since 04. Would exhaust leaks cause this, because i noticed some of my band clamps were leakin a little.
whoa wait. so your gauge only measures vacuum AFTER the egr solenoid? so 98% of the time you drive the gauge reads 0?
you need to clarify where you vacuum gauge is:
exhaust leaks probably wont cause it. i know of a case where exhaust pressure affected egr flow, but i cant recall exactly what it was.
you need to clarify where you vacuum gauge is:
Thread Starter
Joined: Jul 2005
Posts: 5,897
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From: Ft. Wayne, IN
There is a three way tee that is hooked into the side of the manifold! The first port the solenoid is hooked to. The second port is hooked to the guage in the car. The guage reads 18in of vacum at idle. When I pull the vacum line off the egr valve there is no vacum present at the line, but the guage still shows 18in of vacum. Hope this is cleared up
ok thats all normal then. the solenoid wont allow vacuum to the valve at idle.
i dont recall you saying but have you opened the valve with your hand and felt the idle drop? if it works then i can safely say you've got an electrical problem. check the wire harness see if youve got any problems. if it all looks good and youre willing to, throw an egr control solenoid on it. i think its pretty cheap. thats most likely the problem.
i dont recall you saying but have you opened the valve with your hand and felt the idle drop? if it works then i can safely say you've got an electrical problem. check the wire harness see if youve got any problems. if it all looks good and youre willing to, throw an egr control solenoid on it. i think its pretty cheap. thats most likely the problem.
Thread Starter
Joined: Jul 2005
Posts: 5,897
Likes: 254
From: Ft. Wayne, IN
Thanks! I will try these two things tommorrow and get back with you. Also one more thing, should I take back the new egr sice it did not fix the problem.
Another possibility is that your headers/exhaust isn't creating enough backpressure for the EGR to work properly. I would just get some block off plates and a vacuum cap and have it tuned out.
