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Clifton B.
Clifton B., ASE Master Auto Tech
Category: Nissan
Satisfied Customers: 3780
Experience:  ASE Master Certified Tech, Nissan Master Certified Tech, 12 yrs. experience in auto repair.
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1998 Nissan Maxima GLE: malfunction..egr fine..revving

Customer Question

1998 Nissan Maxima GLE - getting EGR malfunction code, replaced the EGR valve earlier this year. Cleaned out all lines I could access. Valve seems to work fine, can see the diaphragm move when revving a warm enginer to 2000 rpm. What is the most likely cause for the malfunction code? Can blockage be a problem, and where?

Just for my understanding, the pipe that connects to the EGR valve is the exhaust (backside of engine), correct? I could not access the other side of that pipe to see if there was any restrictions or plugs.
Submitted: 4 years ago.
Category: Nissan
Expert:  Clifton B. replied 4 years ago.
hi, if the valve move /open then the system is working fine , so if you have a code then that means you have a clog in the system , remove and clean the metal line that go from the back of the intake manifold to the exhaust manifold and clean the intake manifold where the line bolts up to it, this should fix the problem , if you have more question please ask.
Customer: replied 4 years ago.

OK, help me visualize the answer. There is a pipe that goes from the right of the EGR valve (as I look at it from driver side of engine), that is the exhaust, right? How can I access the other end of this pipe (from below, etc), as I can't seem to see where the pipe goes? Or is it unlikely to be blocked?


Where do the EGR lines connect to the intake manifold, I don't readily see that? Where the EGR valve is bolted to, is there a exhaust/intake connection there? I have tried to clean that area but there doesn't seem to be anything but an engine block.

Expert:  Clifton B. replied 4 years ago.

there is a intake to egr valve connection that is what you wanna clean , you will have to remove the upper intake to get access to the pipe

Customer: replied 4 years ago.

Attachment: 2011-10-31_160532_nis_air_manifold.doc


Hopefully you can see this graphic. Is the connection that I want to clean the EGR tube (item 14120)? Is the upper intake manifold that I have to remove the large cast manifold seen on the left of the drawing?


When operating properly, does the exhaust flow go through the EGR tube, through the valve and then through the EGR guide tube which is where it enters the air intake?

Expert:  Clifton B. replied 4 years ago.
hi, sorry i cannot open the file you sent but yes the tube is the egr tube that is what need to be clean , and yes the large cast manifold is the part you have to remove ..
Customer: replied 4 years ago.
What's the trick in getting the upper air intake manifold off? I have removed the bolts on the front and the two in the back, plus a third that I am not sure what that went to. I can rock the manifold a little so the cast part is loose but I can't figure what is keeping me from pulling it up. I did remove the air intake at the air filter so it isn't that.

Expert:  Clifton B. replied 4 years ago.
in the back there are two bolts that hold a bracket to the manifold then two more holding the egr pipe to the manifold and one holding the power steering hose bracket , focus on the back drivers side that is where the pipe is .
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Customer: replied 4 years ago.
I have the two bolts on the backside of the manifold off.

I have one bolt of what I suspect is the egr guide tube off as well, I need the other according to what you wrote.

I need the bracket bolt holding the steering hose bracket, where is that one located?

That should do it, correct?
Expert:  Clifton B. replied 4 years ago.
yes that should, the egr tube have two bolts then one on the pass side center of the manifold .
Customer: replied 4 years ago.
ok latest. I believe I got the bolts out as I can lift the plenum. I do have resistance keeping me from rotating the plenum out of the way. I assume this is the wiring running above the plenum. Any tricks to getting the plenum out of way of the egr tube.
Expert:  Clifton B. replied 4 years ago.
this may be the coolant hoses that run under the throttle chamber check that ,
Customer: replied 4 years ago.

I was able to the move the manifold enough to get the egr tube off. I cleaned it really well, can't say I saw a lot of pluggage so I have a feeling that wasn't the problem. I could only poke a finger through the exhaust where the tube connects, I didn't feel any pluggage there as well.


I did however squeeze a finger between the manifold and the egr guide tube connection. I expected an opening but I really didn't feel one. If there is supposed to be one it seems really plugged. Since I couldn't get the manifold off completely I couldn't get a good look. Several hoses kept me from getting it off, they were a pain.


Put it all back together and ran the car a bit but scan on the EGR system was still incomplete. What would be my likely next problem?

Expert:  Clifton B. replied 4 years ago.

i did say that you will need to clean the connection between the tube and the manifold that is where they clog up , right where that tube bolt on to the manifold . you need to be able to see in the back of the manifold.

Customer: replied 4 years ago.

By my drawing, there is an egr tube and an egr guide tube. The egr tube connects to the exhaust, that is what I cleaned. The egr guide tube connects to the upper manifold, two bolts and it looks like one bolt to the egr valve spacer. Can I not just remove the three bolts and try to unplug it that way? They seem relatively accessible given what I did yesterday, I really don't want to remove the manifold again if I don't have too, plus I couldn't disconnect some of the tubing, any tricks to the trade there?

Expert:  Clifton B. replied 4 years ago.

the egr tube that connect to the upper intake is where the clog is, the tube have two bolt to the intake ,and two at the bottom of the tube where it connects to the egr valve , it is very hard to get to the two bolts on the bottom that is the reason for removing the intake ,

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