hermtm2

iTrader: (1)

Hi.

I've got CEL to 0400 which is EGR lean flow deteced. I replaced the EGR valve and gasket by OEM but the CEL shows me up again. I don't know what is wrong? Can you guys help me out?

Thanks.

nhaven

You probably have a clogged egr tube. Something similar to this ..






EDIT: adding another pic

bhunter

iTrader: (3)

^^^ What he said. Clean it with solvent and a piece of 1/4" aircraft cable on a drill.

hermtm2

iTrader: (1)

I will try to do that and then let you know.

Thanks.

UncleMax98

Before you try to clean the EGR tube, check the EGR-C solenoid first. It is near the automatic transmission dipstick and has a green electrical connector. The solenoid has three vacuum connectors. One on one side, and two on the other side. Without 12V power, the air flows between the middle vacuum connector and the other end. With 12V power, you should hear a loud click, and air flows between the two vacuum connectors on one end. If you have an Ohm meter, you can measure the solenoid coil resistant. You should get about 30 - 40 ohms. If you get 300 or more ohms, it is likely to be bad.

If the coil is okay, there are other causes, clogged vacuum tubes, air leak, temperature sensor, etc.

Clogged EGR tube is also a possibility, but you should do it last. The cleaning the EGR tube is not easy.

dvpatel99se

iTrader: (1)

It seems that darn clogged tube is the most common cause around here. I too have the code. But have not yet opened up the car. It drives fine so I am being lazy.

nhaven, do you have more pix? I want a wider shot of how it looks when TB and IAC are removed and I also want to see what all needs to be removed. One of these days, I need to get this done. Wife's been *****ing about the CEL.

Morpheus2010

iTrader: (2)

I have the same problem and my mpg is down a lot

hermtm2

iTrader: (1)

I'm screwed up now. The green sensor was broken when I took one of the rubber hose. I have to buy new sensor. What is the name of green sensor? Can you give a part number?

Hunter11

iTrader: (1)

I finally did this today and it looked just like the pics above. I got everything back together and now it is idling really rough. Can anyone suggest anything before I have to go out there tomorrow and take everything back apart?

Unless I am missing something all of the connections are back on there correctly and I don't know what else to look for?

maximomo

iTrader: (2)

It will idle rough for a while after you do this job.
You need to drive it a couple mile to clear all of the crap out of the system. If you have done that then you have a vacuum leak. You can find it easily using some intake cleaner. Just idle the engine and spray in spurts near the vacuum lines and the EGR tube. If the idle changes you found the spot.

Did you connect the vacuum line back on the bottom of the throttle body?
Did you use a NEW gasket on the EGR tube to manifold connection?

knight71

Hey Herm
The part goes by 4 names
1) EGRC Solenoid Valve.
2) Purge Control Valve. This's what it's listed under on Jerry Rome Nissan .com
3) Valve Assembly, as it's called on my invoice from Jerry Rome Nissan. Part #14956-31u10
4) EGR VACUUM SOLENOID. This's what Autozone calls it.

hermtm2

iTrader: (1)

That's exactly what I need now. As soon as the CEL comes out again, I will order the solenoid.

Thanks a lot.

hermtm2

iTrader: (1)

I got the CEL again. I think the solenoid should be ordered.
Thanks.

Hunter11

iTrader: (1)

The problem was that the gasket on the EGR tube to the manifold was only half on. I guess it slipped off putting it all back togethr. But I have never had a vacuum leak but they will really make the car run rough. Anyway, my car is still throwing th EGR 0302 code.

maximomo

iTrader: (2)

0302 is a cylinder #2 misfire code NOT EGR.

You probably have a dirty or bad injector.
Move the injector to cylinder 4 or 6 and clear the code. If it comes back on 4 or 6 you need to replace the injector. If not, you have a coil or spark plug issue. Move each of those one at a time to 4 or 6 and see if the problem follows. I think you get the drift of it from there.

maximomo

iTrader: (2)

Why don't you just test the "solenoid"? ground one connector and hit the other one with 12V. If it clicks it's good. If not, it's bad. If it's good you have a bad vacuum line or something else.

hermtm2

iTrader: (1)

I replaced the solenoid today because the old one was broken when I took it out. I put the solenoid (used one) and new rubber hoses. In addition I cleaned the EGR tube up and replaced the EGR valve and solenoid. It still has CEL. What else I can do?

Thanks.

maximomo

iTrader: (2)

I presume you cleared the codes after doing all of this work.
You should pull the code(s) again and tell us what you find. Do you still have P0400?

If so, you need to test the EGR temperature sensor and wiring to make sure it is good.
The temp sensor should be between 76.8 and 93.8 ohms when hot(212 degrees). The best test is to check the resistance when the engine is cold then check at normal operating temp after driving it a couple of miles. The resistance should change and it should be in the range stated above when hot. If not, it is bad.

If temp sensor and wiring is good I would triple check that you don't have a vacuum leak in the EGR control system.

hermtm2

iTrader: (1)

I will check the vacuum hoses, solenoid, and temp sensor again.
Thanks.

hermtm2

iTrader: (1)

I replaced the vacuum hoses, EGR solenoid, and EGR valve and then cleaned the tube up. However the same code 0400 comes up this morning. What I have not checked is the EGR-BPT valve with the tube. How do I know the EGR-BPT valve is bad or not?

Thanks.

maximomo

iTrader: (2)

Technically, if the EGRC-BPT valve is the issue it will throw the code 0402.

There is a procedure in the FSM that tells how to test it. It's convuluted and you need to plug one side and blow into the tube in the other. You also have to run the Fuel pressure regulator vacuum hose into the EGRC-BPT valve vacuum hose and check the lift of the EGR valve.

Personally, I would assume it's NOT bad if you didn't get the 402 code. I tend to think there is still something clogged in your EGR port. Did you take out the temp sensor and clean out the hole between the sensor socket and the main EGR port? When both of mine got clogged that was clogged as well. On one of them I failed to clean it out the first time and still would get random 0400 codes once in a while. The sensor is easy to take out and you can use an awl or small tip screwdriver to ream out the hole. Then spray in carb/throttle body cleaner and reassemble. Takes about 10 minutes.


Also, Both of my BPT valves have been kind of funky. Meaning, the foam ring inside fell apart in places. So, I used some high temp gasket goop to seal off a section of it just to make sure there isn't a direct opening to outside air. The foam ring is supposed to act as an air filter--not much else. I doubt this has any impact on your problem.

papo020

If it is the coil i'm gonna give you a quick cheap tip. Sometimes you get a little moisture in there. Take a little WD-40 and spray it directly on top of the spark plug and also into the coil pack. With the coil pack out turn on the car and let it spit out all the excess liquid. After about 30 seconds shut off the car and put the coil pack back in. Turn on the car accelerate it about another 30 seconds. If it was moisture that should fix it.

hermtm2

iTrader: (1)

I'v got what you talking about it except for a meaning of "the foam ring inside" which is underlined. Can tell me about the foam ring more specifically or show, if you have a picture of that?

Thanks.

maximomo

iTrader: (2)

I can't upload an image here but I can email one to you from the FSM.
PM you email address and I'll send it over.

The EGRC-BPT valve is essentially a disk shaped unit on top of a disk shaped diaphram. The diaphram (bottom piece) has a needle valve in it that is pushed up by exhaust pressure. This closes off the air inlet to the vacuum lines and allows the vacuum to raise the EGR valve diaphram to open the EGR. When the BPT valve isn't seeing exhaust pressure the vacuum inlet is open to outside air. This outside air bleeds in through a foam filter which is a ring of foam between the two disk shaped pieces. Again, the foam doesn't serve any purpose other than to filter the air and it isn't all that great a filter. Since the amount of air entering this port is miniscule it isn't a big deal even if your filter foam is totally gone.

I'll send you the picture and it will make more sense.

7jackmack

Uhh-- Did you clean the port in the intake plenum that the egr tube
connects to??
When I had the 0302 code at around 200k ,I removed the iacv and cleaned
the port for the egr tube -but did NOT remove and clean the the tube itself.
That was enough to clear my code . 6 months ago, I had to take off the
plenum to do the rear valve cover , and while I was there I checked the egr
tube and found it had very little carbon accumulation .This was around
290,000 miles .
So basically the only area of my egr system to ever clog has been the
port "trough" in the plenum that the egr tube bolts up to.
(also- I'm the original owner so I know nobody else has cleaned the tube)

ahallmaxima

I've got a 2000 Maxima GLE, 96K miles. I replaced my mass airflow sensor because the car was throwing P0171 and P0174 and running sluggish. With new MAF the car runs much better and no more P0171/P0174 but now I'm throwing P0400. I've reset it a few times and P0400 keeps coming back, even after 200+ miles driven. It shows up only when I am slowing down/almost stopped or idling, never on the freeway.

Talked to a Nissan service manager today who suggested the EGR valve needed to be cleaned and perhaps replaced (although of course he couldn't tell for sure without hooking it up to a computer). I said I've never gotten P0400 before, EVER and now I'm getting it after between 10 to 60 miles driven. He said it's possible that when the computer would throw P0171/P0174 it would stop the computer from showing any more codes - does that make any sense?

I was sure I must have done something in replacing the MAF, disconnected or broken a vacuum hose or something. Couldn't imagine the valve suddenly showed up as a problem just after I replaced the MAF. But I put the old MAF back. Just drove it about 50 miles. Got P0174 again once but no more P0400.

I didn't think I needed the ECM reprogramming with this MAF replacement - but is it likely this could be needed to prevent this P0400? Or could the service manager be right that my bad MAF was preventing the already-present EGR problem from showing itself?

maximomo

iTrader: (2)

Take the temperature sensor off the EGR port tube and look inside or stick a small screwdriver in it and see if there is carbon build up and clogging. If there is--you need to clean out your EGR port. This is a common problem on Maxima's. The fact that it didn't show up until you replaced your MAF could be for a number of reasons. It's very unlikely that you could cause a P0400 by doing anything related to the MAF. P0400 is an EGR flow issue triggered by the EGR temp sensor.

ahallmaxima

Thanks, I will look at this - although I still don't know why P0400 would then go away once I went back to the old MAF if the EGR temp sensor was clogged - unless the service manager was right and the computer simply won't flag the problem as long as there are other codes.

maximomo

iTrader: (2)

I believe the computer will avoid logging P0400 when there are other codes because there are other issues that can cause a phantom P0400. It can't hurt to check and clean out the EGR tube anyway. It WILL need it sooner or later. They all do.

ahallmaxima

Right, that's what the service manager suggested as well. However, consider this: with the old MAF, I've now driven 80 miles and no codes. I put my OBDII reader on and scanned - and all the tests except O2 sensor show as ready and that includes the EGR system. With the new MAF it would throw the P0400 code long before that.

Very true. My immediate concern however is getting this thing through emissions before my registration expires in about a week, and cleaning the tube sounds like a pain especially for someone like me with limited mechanical skills.

The car is running OK at the moment with the old MAF and a new air filter and I'm taking it on a road trip on a nice, clear day. No codes for 80 miles. If I can get it to go into O2 Ready for testing I'll head to a DEQ station and get that sucker through - and then worry about the new MAF and fixing the EGR code.

Thanks again.

Morpheus2010

iTrader: (2)

Ok well my mechanic finally found out the problem. The car was loosing vacuum in the Air duct. here is the part number we took off it 31u17. I'm not sure if that's correct. He even plugged up the tube that goes to the air duct to prove that it was the problem. SO have your mechanic do a vaccum leak test on everything to make sure they are all working. I've already replace my egr valve and the soleniod works.

Morpheus2010

iTrader: (2)

Well the answer for my problems is definitely the resonator box/air box. Since the mechanic plugged up the hose going to it as a temporary fix the check engine light has not come back on since. I already order it $65 from nissan online.

bigblock261

I thought I would share my experience. I have a 99 GXE with California emmissions. I believe the EGR hardware is slightly different from the Federal, based on the local Kansas City area Nissan parts dealer not having the EGR valve in stock.
Background: I'd been driving for months with the P0400 CEL. I read up on how to fix it in these forums. I pulled the customary components off and found the tube from the EGR valve to the intake plenum packed solid with carbon. Miles are 128k. I cleaned the tube out with carb cleaner and a foot of cheap 1/4" wire rope from Ace hardware, by hand, a drill wasn't needed. I also cleaned the exposed portion of the EGR valve as best I could with carb cleaner. Afterward I disassembled the EGR valve but found nothing remarkable, then reassembled it. The CA EGR valve is actually a stepper motor. I found and removed an impressive plug of soft carbon in the EGR inlet to the intake plenum. I cleaned up the IAC and all the gunk I could out of the intake plenum and put everything back together using new gaskets for the IAC and throttle body. I cleared the code, fired it up and instantly got P0400. The car ran fine. I drove it about a week, cleared the code, but no joy. P0400 CEL instantly back on. I checked the EGR temp sensor with an ohmeter - checked good. I then ordered a new EGR valve without checking the original one with a meter. By the time the new EGR valve arrived the CEL WENT OUT by itself! And yes the bulb is good. The elapsed time was about three weeks of normal driving. I believe I squirreled up the EGR valve by messing with it, and it took quite a few cycles for it to normalize. Either that or the tip of the EGR temp sensor got contaminated by me somehow, and it took time for exhaust gas to burn it clean so it could start making proper voltage. I'm happy. Thanks to all for the good comments and pics. I don't recommend disassembling a California EGR valve. Clean it if you wish, but leave it together.

alexthedroog

i've been having the same problem with CEL and the EGR valve area.. My car is a 98 maxima and the mechanic replaced the valve..the CEL went out for a while but them came back on a few weeks later. They can't find what the problem is but said it wasn't something that would damage the car it was just an emissions issue. They also said searching for the problem was akin to chasing ghosts and could get expensive...

should i just live with the CEL light on or try to fix the issue?

whiteSE

iTrader: (2)

lol. NO!!!!


everytime i fix something, something else breaks.

dvpatel99se

iTrader: (1)

Ok fellas. I have been lookin for that green connector to no avail. I think mine's brown. I have a 1999 built in the middle of 1998. Here are a couple of pix. http://dvpatel.homelinux.com/online/...geViewsIndex=2
http://dvpatel.homelinux.com/online/...geViewsIndex=2

Is the brown thingy the EGRC Solenoid? It does have three tubes coming out (one on top) but each one of the rubber tubes don't budge at all. I cannot even get to the connector to unhook it. I was able to remove it and turn it a bit but the darn electric connector still didn't come off.

Am I on the right track?

oldngivout

iTrader: (8)

The one pictured with the brown connector is the MAP/BARO solenoid.

dvpatel99se

iTrader: (1)

Ok. Then where is the EGR one? I cannot locate it near the tranny dip stick tube as mentioned in posts and pictures.

ATTappman

From the FSM it doesn't look like a 99 Fed spec has an EGR control solenoid valve. Why are you looking for it? If you're getting a P0400 code, the manual mentions an EGR volume control valve. That's not the same part as the EGR control solenoid valve that's on the 95-98 models. See page EC-14 in the FSM for the location of the EGR volume control valve.

dvpatel99se

iTrader: (1)

Yes. I have a P0400. I have had it for a couple of years. Need to get off my lazy behind and take care of it.

All the P0400 threads mentiona bout the EGR Solenoid and hence I was looking for it. No wonder I can't find it coz it don't exist on my car. I will look for the volume control valve as you mention.

Thanks