I own a 99 Maxima and its service light came on about a month ago.
Running a diagnostic test revealed that there is something wrong with my EGR (PO400). I am trying to correct this problem on my own, but I am having trouble finding the damn thing. The service manual for 95~99 shows exactly where that thing is located, but on my 99, IT WASN'T THERE (..the mushroom head looking thing...).
When I called my dealer, a mechanic told me that EGR on 99 is a little different and he suggested to bring my car in.

CAN ANYONE PLEASE TELL ME OR SHOW ME SOME PICS WHERE EGR IS LOCATED ON MY 99? IF YOU REALLY WANT TO HELP ME, CAN YOU ALSO TELL ME HOW I CAN FIX THIS PO400 PROBLEM. I KNOW THAT NOT ALL PROBLEM ARE THE SAME, BUT IF YOU CAN SHARE YOUR EXPERIENCE, THAT WILL BE GREATTTTTTT~~~

 

Anyone? please.....?

 

Here are some links that might help you:

EGR component location photos: http://photobucket.com/albums/v158/evilBIGD/EGR/

EGR how to check:
http://forums.maxima.org/showthread.php?t=260406
http://forums.maxima.org/showthread.php?t=259590

EGR Cleaning:
http://forums.maxima.org/showthread.php?t=276033

EGR code 0302:
http://forums.maxima.org/showthread.php?t=245494

These are all that I've bookmarked for EGR issues. You can use this free search link if you need to look for more info: http://search.yahoo.com/search?p=ste...ums.maxima.org .

My Chilton service manual is only for 95-98 Maximas. So I'm assuming that the code you have indicated below is probably different on pre-99 Maximas (I could be wrong). BTW, how did you get that code anyhow? The surest way to check is to follow these instructions: step1, step2. Hopefully this helps.

 

This link will help you determine the actual codes that you are getting from the ecu:
http://forums.maxima.org/showthread.php?t=104931

It's in the 4th gen stickies (faq). That P0400 is 0302. The 0302 code comprises of sequence of CEL light pulses, long pulse represent the first 2 digits and short pulses represent the last 2 digits. It is very useful to familiarize yourself of the procedure for extracting codes from your car's ecu, as this will save you money that dealars will love to take from you. This is a good place to start: http://forums.maxima.org/showthread.php?t=245494 on the 0302 code. I've personally haven't seen a 99 owner post this type of problem so I'm not familiar with the 99 EGR orientation. I'll see if I can find a photo and will post when I do.

 

If you end up checking your ecu yourself then you will need this sticky as well...since you're a '99:
http://forums.maxima.org/showthread.php?t=363154

-Jeff

 

Thanks everyone..... however I still cannot locate my EGR.
ALC252DM, I have that diagraham, but it does not apply to 99 Maxima.
That mushroom looking thing (EGR) is not on 99 Maxima....

BTw, i got the code from a local dealership...They charged me like $30.

 

Hopefully now you don't have to keep paying the dealer to extract codes from the ECU. I understand that the EGR location on a 99 is different. Someone on the org (with a 99 I think) just resolved his EGR issue (combined with misfiring). I am going to try and find the thread and maybe you can PM him. He said he changed everything in the EGR system so he knows where the EGR is. All I know is that you cannot find the EGR w/o having to take things off of the car. Like in my 95 Maxima, the EGR is burried below the whole air intake assembly and throttle body. I had to remove the airbox, MAF, and resonator before I was able to find the EGR. You have to move some vacuum tubes out of the way. If you are familiar with this, you might want to start taking these things off, you should find it.

 

I finally found what you are looking for (courtesy of erbentraut), click here. Also, read this thread which is specific to 99 Maximas like yours. Hope this helps.

 

Thanks for the info..definetely help 99 owners

 

Damn, this is great!
ALC252DM, thanks for everything.
Let me check these out!!!!

 

Let us know how it goes. Goodluck.

 

My scanguage is reporting error code PO400 too (1996 Infiniti I-30 w 100k+ miles). Autozone says its a bad EGR valve, costly too. Any suggestions? Can it be cleaned?

 

clean the tube where it bends downward. Usually where it gunks up.

 

You can check the tube for gunk! If not(no gunk), and you have over 100k miles, I would just replace the EGR valve. I replaced my tube and then had to replace the egr valve anyway. ALso there is a thermistor in the intake that sends info to the ecu about when to open the ECR valve. That could be tested for failure. Haynes or Chilton's manual could help with the troubleshooting.

 

ok, i just got the egr 0302 code as well. to check the valve, you just apply vacuum to the egr vacuum port and if the spring doesn't lift, you need a new valve right? how much are they?

plus, what do you use to clean the hoses, TB cleaner?

 

99 models use a stepper motor controlled by the ecu. It uses that thermistor to sense how much to open and close the egr valve. P0400 and 0302 are the same. It just points to the EGR system flow as your problem. On the 99 Max's the stepper motor is part of the EGR valve. If you have a 99 just replace it for around $100.

The earlier models use vacuum hose to control the egr system. Much more prone to hose leaks. EGR systems suck eggs

 

Subscribed

 

 

So i got code P0400 and it failed the emission test so I can not register it until it gets fixed. The shop that failed me also diagnosed the problem and said they ruled out everything else, so it must be the EGR valve. They quoted me $360 at which point I started laughing and walked out. I bought the part myself for $120 at Autozone and installed it fairly easily. The light stayed off for about 30-40 miles but eventually came back on, same code. I double checked everything on the new valve, but it is installed correctly and does not seem to be defective. I am guessing the shop I had diagnose it didn't really look at much. Any suggestions on what else it could be and how i could check it? I appreciate any help!

 

Verify the EGR valve is working properly per FSM. Check for any EGR leaks. Check gas cap. Check the rest of the EGR componentry. Clean MAF, TB, and IACV per how tos. Check condition of plugs.

Run a can of Chevron Techron in the fuel tank. May require two applications of the techron to really clean out EGR.

If that dont work, SEAFOAM that bish.

If that dont work, clean EGR guide tube per how tos.

EDIT:
Im guessing you have lots of carbon buildup in the EGR system. U prolly didnt even need the new EGR valve. Jus really need to clean the tubing. Chevron techron will help with that. Seafoam too. EGR tube removal/cleaning is last resort as this is a PITA

 

Thanks for some ideas. I will go through and do it tonight....

I think my original EGR valve was fine too, but I was foolish enough to just trust the shop without diagnosing it more first myself.

And I can tell that the EGR tube removal/cleaning is a total PITA!

 

Yes, and unfortunately it's your only fix at this point.
Chevron, Seafoam - your wasting your time and $$$.

Search these forums for detailed pictures of the EGR tube, remove it and you'll see what's involved in cleaning the gunk out of it. Your 99 isn't going to be easy, I couldn't even get mine tube completely out. Cleaning it wasn't easy either, lots of solvents, a thin wire snake, compressed air and about 3 hrs was the job on my 99.

Good luck!

 

Before removing the egr tube and cleaning it, you might try removing the IACV and spraying some throttle body cleaner down the tube. The last time I had a P0400 that cleared mine up. I think it's just easier to replace the tube instead of cleaning it.
But the throttle body cleaner might get you going thru emission.

 

i just replaced the entire egr system the other day... ive had the code since i got the car march of last year. did the seafoam twice, ran this 44k stuff that they had at Courtesy parts, cleaned the tube out, checked for leaks, always ran shell or chevron... when it comes down to it, i just spent the money on all new oem parts, replaced them, and im code free for 400+ miles now... just take the dive people, cleaning the tube is only a temp fix if the system is already clogged. only thing i didnt replace was the sensor. I could have also gotten away without buying the header transfer tube part too...

just my $.02

 

I look at the chevron and seafoam as preventative.

but i know, If the po400 code comin up then it may already be too late.

Still i think he shd try the chevron and see if it can help. EGR tube is such a pain, i CANT recommend that as first solution especially if a 10 bottle of chevron or TB cleaner may do the trick.

I agree with plumm too...if the tube is that bad. Fck cleaning it, jus buy a new one from nissan with the gaskets.