I give up! CEL P0401 is BACK

Ok, here's what all I've done as a recap.

Last October was the very 1st time I'd ever seen the CEL light come on, steadily. Not blinking.

Didn't think too much about it, had a run in with some very bad gas that caused the truck to idle weird (but not high), stall twice, and chug - got it down to half a tank and filled up with Shell gas. Problem instantly went away after about 6-10 miles.

But after 2 more tankfulls, CEL was still on.

Autozone code read "insufficient EGR flow"

Cleaned EGR; CEL stayed off for 2 months; came back on in December, same code. Cleaned EGR again, stayed off til January.

In January, I had a full-tune up, plugs, fluids/filters, belts, 4 new O2 sensors, waterpump, camshaft/crankshaft seals, timing belt/tensioner, idler pulley, and starter have all been replaced.

CEL code came back on in February, still the same EGR code - per Autozone.

Cleaned EGR again, CEL stayed off til sometime in April.

Since then, it comes on for 2 days, off for 2-3 days and back on again. CEL is not blinking, but steady, and truck runs great irregardless, idle does get a *tad* rough after it comes on, but idles at the same rpm's whether it's on or not.

2 weeks ago, I took off the whole air intake hose, cleaned it out, along with the Throttle body, MAF sensor, PCV valve and such. Air filter still looked fine.

CEL stayed off for the whole 2 weeks, then came back on yesterday!!! Again, same code, no symptoms for anything.

Two things of curiousity, what do I have to lose at this point - EGR gasket has been removed several times, but I haven't replaced it with new. Gas cap *looks* fine, and I always make sure it's on tight - BUT, you know how on most cars when you loosen the cap to fill up, you can hear air escape, like you know it's had a good seal. I haven't heard that sound in forever on the Rodeo, but I get that same sound on my other vehicles.

Any ideas are more then welcome?? My next two moves, are new gas cap and EGR gasket. Not gonna replace the EGR itself, yet.

I'm trying to narrow this down, as obviously it won't pass emissions and seems to be a problem I can't trace. I did get my tags for this year, but next February it has to have an emissions, and I don't want to wait til the very last few months trying to solve this stupid situation.

FWIW - was wondering if it was the cat convertor getting clogged, but the truck has too much power, doesn't act like it's congested.

I'm thinking the internals of your EGR are getting questionable. Instead of spending all the money on a new one at the moment try pulling one from a salvage yard. If you cant find an isuzu one get one from a mid-late 90's GM 3800 v6. Its identicle and works. I dont know if the egr gasket would leak enough to cause enough of a problem to throw a code.

As far as the gas cap, I've never heard pressure release from mine. I've never had a CEL *knock on wood*.

I'm no expert, but if cleaning the EGR works for a few weeks, then same code..wouldn't it make sense to replace the EGR?

go to the junkyard and get one. I got one for $15 and it works well so far.

Just a cheap fix is to run a can of seafoam through the pcv valve.

Ramblin, I don't recal if it's in your other threads in regards your EGR woes, but what type of EGR system do you have? Does the 1997 3.2L have an electronic EGR valve like the 1998+ or is it vacuum actuated like the 1993+ 3.2's? If it's electronic (solenoid type valve), just replace the valve. With all your cleanings, there no way its clogged. If you have a vacuum style EGR vlv, you have to look into the differential pressure switch on the EGR plumbing that measures flow. Some vacuum actuated EGR systems rely on a MAP sensor to sense flow as well, but your 3.2L uses a MAF sensor instead. Gas caps & PCV dont have anything to do with EGR.

Joel

It is an electronic EGR valve like the 1998+. GM part from 3800 v6 fit fine, through connector may be on other side.

Like you, I was beside myself, and was told a number of different things from a number of different mechanics.

After I replaced my second EGR, I still had the CEL.

We ended up haveing to pull the top and lower manifolds to get to the clogged tube that ran from the EGR.

It was completly clogged......and there was no chemical that could clean it.

it had to be removed and we had to use tools to break up the carbon build up.

Ended up selling the other fairly new EGR on Ebay.....

Repair job cost me around $300 in labor

..We ended up haveing to pull the top and lower manifolds to get to the clogged tube that ran from the EGR.

It was completly clogged......and there was no chemical that could clean it.

it had to be removed and we had to use tools to break up the carbon build up.

If your rig is a 1998+, there was no need to touch the common chamber & this could have been fixed with a coat hanger and some basic tools. All you have to do is 'roto-root' out the EGR tube with a coat hanger or the likes, from the EGR valve base, to where it exits behind the throttle plate. Verify the coat hanger will go all the way thru and you are good to go. No need to pop the common chamber apart (upper intake) on the 1998+ for an EGR cleaning anyway.

Joel

Ok, haven't had time to really look at the Rodeo, the Toyota's been stealing all the attention again - attention hog!!

Anyway, I'm pretty sure it's called a Linear EGR set-up, i.e. guessing vacume type set-up, in which the only thing left - I believe - that I haven't checked is the MAP sensor, but I don't have the tools to check it out.

I will look into it this weekend to see if there's anyway I can clean it, check for any broken wires/loose connection etc., other then that, I'm at a loss.

I need to do something though, as whenever the CEL is on, the truck drinks gas like it's going out of style, and it's been on all this week hasn't shot off yet. I'm also feeling a very slight loss in power going up the on-ramps.

Rodeo02 - you mentioned the MAF sensor as part of the EGR issue, I've already cleaned this twice; is it still possible to be part of the issue?

..you mentioned the MAF sensor as part of the EGR issue, I've already cleaned this twice; is it still possible to be part of the issue?

My thoughts are since your 1997 3.2L has a MAF sensor, it may not have a MAP sensor. You *usually* dont have both as a MAP is the predecessor to newer MAF based systems. MAF in itself is completely unrelated to EGR. Are you SURE you have a vacuum actuated EGR valve? It's real easy to verify this. Does the valve have a vacuum dome on w/ vac lines, or it or a cannister type electric solenoid with a harness/plugs?

Joel

Will verify more when I pop the hood later, but I can readily tell you that it looks like an upside down canister with one electrical plug and two bolts holding it on - that's it. Real easy to take off.

Hoping that it's of the electrical and easy fix would be to just replace??

Per the Haynes manual, which I'm not totally confident in, shows a picture of a MAP sensor on a 3.2L engine, however it could be of an older model and not the '97 year.

I definitely have the MAF sensor, and I can always try cleaning it again. And like I noted above, I've reopened the EGR several times, but have never replaced the gasket - could this simply be the issue?

Ok, truck definitely has a MAF and a MAP sensor. The MAP sensor is located on the passanger side of the truck just above the 2nd spark plug from the back of engine towards the front.

It looks like the clip from the MAP sensor wiring harness that clamps over the MAP sensor is broke; but the two definitely have a tight connection, from what I can tell.

I wiggled the connections a bit, and nothing appears loose; but after I did that, when I restarted the truck, it acted a little hesitant in momentum - only lasted about 2 blocks though.

Keep ideas coming please!

So is the EGR valve electric or vacuum? You have physically removed it before, correct?:uhoh: If the EGR valve is electric, the MAP sensor wont have anything to do with it.

Joel

Ok, YES, finally got back to it; it is electrical as far as I can tell. If you were to remove it, it's 2 bolts, and a electrical harness - that's it. Looks like an upside down canister, and there is no vacuume lines attached to it, specifically.

Sorry for the delay, had to double check everything, as my 1st rodeo DID have a vacuume EGR system, and I had been looking up everything pertaining to that type.

So, is an EGR valve in need? Thinking back, I wonder if I didn't do something to it - I dropped it the 1st time I cleaned it, not hard, but wonder if that was enough.

So, is an EGR valve in need? Thinking back, I wonder if I didn't do something to it - I dropped it the 1st time I cleaned it, not hard, but wonder if that was enough.


I recently replaced mine (junkyard, $15) and I too was thinking back for causes. Mine was dropped as well, but I also wonder if it's a bad idea to spray cleaner into the pintle? Maybe I didn't let it dry enough, maybe it was unrelated, but something caused it to break.

It may be worth a shot to go to a junkyard and get a used one cheap, that will at least tell you if it's the EGR.

My only concern is yours is saying the flow is insufficient. But, you've cleaned it quite a bit, so I don't know. Maybe it is worth another cleaning. Get into the tube with a coathanger or something.

marc

..the wife`s has been doing the same thing...what I`ve found the plunger is sticking into its seat..angles of the seat or plunger could be the culprit..I push back the plunger clean what carbon there is there usually there is nothing but a little soot..then I use a little anti-seize on the plunger/seat and its shaft..I have found the gold high temp seems to last longer..its just a design flaw..harder seat and different seat angle could alleviate this..:wink:

I just cleaned my EGR for the same reason. Here is my suggestion for a quick but quality fix, unfortunately I removed my entire intake to fix this. :banghead:

Applies to a 2000 Passport 3.2L V6, your milage may vary however it should be identical.

1.) Remove the intake piping from the air cleaner box to the throtle body.
2.) Remove any wiring harneses (my TB is drive by wire) and cables that are attached.
3.) Remove the 4 bolts securing the throtle body to the common chamber (intake plenum).
4.) Finagel throtle body out of the way, or disconnect the coolant lines on the bottom.
5.) Put a rag or something over the throtle body and something in front of the opening of the common chamber.
6.) Remove the EGR valve assembly from the top of the lower intake manifold.
7.) Connect a shop air line to the smaller opening where the EGR valve was (the one closer to the intake).
8.) Attempt to clear this with compressed air. Spraying gum cutter or the like before hand may help.

Good luck!

-Phil

Thanks, I'll look into that as time allows - the CEL is still coming on, but not as often as before.

I honestly wouldn't worry about it, as it's running great, with or without it on, but I'm worried about not passing emissions next year.

Thanks, I'll look into that as time allows - the CEL is still coming on, but not as often as before.

I honestly wouldn't worry about it, as it's running great, with or without it on, but I'm worried about not passing emissions next year.This is exactly why I cleaned mine, since my inspection expired in Jan. '06. You WILL NOT pass emissions if you don't resolve this. Well in NJ anyways, I'm sure other states would be the same seeing the EGR is an important part of the overall emissions system.

I even failed due to the CEL being on for a bad fuel sending unit :uhoh:.

NJ inspection is terrible.

-Phil

In Colorado, they were talking about putting a stop to emissions testing in the last year - so I'm hoping that passes. This EGR set-up is definitely a bugger!

In Colorado, they were talking about putting a stop to emissions testing in the last year - so I'm hoping that passes. This EGR set-up is definitely a bugger!

Here in Maine we used to have emission testing. So many of the frugal native folks are driving old beaters that the failure rate was high. A group of people got together to challenge the requirement, drove a few lawsuits and PRESTO - the testing program was quickly abandoned less than two years after it started. It's a good thing - every car I drive was made in the last century and would be a big headache above and beyond the strict annual mechanical inspection process we have in place today. The state inspectors will check for CEL's only. If your light is on, you flunk. No light (no black tape on the dash either) and you pass. I was lucky that my '68 Chevelle baffled the inspector. The engine originally had a very basic air pump smog system. But that 'fell off' at some point over the years.:uhoh: So I told them that since the car was built in 1967, it didn't have emissions accessories on East-Coast built cars. He didn't have anything to disprove it, so he put the sticker on the windshield. Now I can use the presence of the old sticker as the reason to get a new one each year. Of course I could be a smart-as* and suggest that he plug in his scan tool to check for codes!:grinno:

I can't believe what I'm reading, there are states that don't bother checking emissions!?!?!? Maybe I need to move, seriously in NJ not only do they put a sniffer up your tailpipe (checking for NOX, CO, and HC's) but they also set your car up on a dyno, run it up to speed with a fan in front to simulate actual driving, all while connected to your OBD-II PCM.

-Phil

I can't believe what I'm reading, there are states that don't bother checking emissions!?!?!? Maybe I need to move, seriously in NJ not only do they put a sniffer up your tailpipe (checking for NOX, CO, and HC's) but they also set your car up on a dyno, run it up to speed with a fan in front to simulate actual driving, all while connected to your OBD-II PCM.

Thats what they do in colorado too, for the time being. They did pass the bill to get rid of that system of emissions testing (the gov signed it last month). But it is being replaced with road side emissions vans that check your emissions as you drive past. If they are too high it will take a pic of your licence plate, after a few fails they send you a letter to get it tested at an inspection station. They dont have enough vans yet though so it may take a couple years for it to actually be implemented.

So, Gizmo, do you know if they're definitely getting rid of the stations? I.E. I don't have to worry come next February ???

The stations will still be there for those that fail the road side tests but we wont have to go to them anymore otherwise. I dont know how long it will be before they actually get rid of the annual testing. The governor said he thinks it'll be a couple years before there are enough monitoring vans to allow them to do that. They are supposed to have a full plan in place by the end of this year and have until 2010 to prove that it works. If it doesnt or isnt cost effectective then the entire emissions program gets scrapped.

There has been one of the vans set up on 225 between alameda and mississippi most days for the past month (usually at the end of the on ramp to south bound 225 from alameda).

Heres some more info if you wanna know..

http://www.bighorncenter.org/accomp.cfm?accomplishmentID=38

I don't think RF has to worry about the P0401 code too much anymore.... Ramblin?? Did u spill the beans over hear yet as to what (new ride) you recently purchased? wink-wink....nudge-nudge....:uhoh:

**EDIT** Oops..I see that's it's in your signature. CONGRATS!

G/luck
Joel

I don't think RF has to worry about the P0401 code too much anymore.... Ramblin?? Did u spill the beans over hear yet as to what (new ride) you recently purchased? wink-wink....nudge-nudge....:uhoh:

**EDIT** Oops..I see that's it's in your signature. CONGRATS!

G/luck
Joel

:nono: :nono: :nono: Sssshhh! Quiet!

Boy, you don't know how to keep a secret, do you?? :rofl: Kidding!

Thank you on the Congrats!

Yep, we added a new ride to our stable, an '06 Nissan Xterra Off-road 4x4 Edition, almost same color as the Rodeo.

I actually hadn't thought to really mention it, as we still have the old faithful (Rodeo) - so, yes, I do still have that P0401 code to trouble shoot, emissions is due in February.

The Rodeo's gonna have to crawl to the junkyard before I get rid of it; she's long paid for and isn't worth too much to anyone but me.

KBB is only like $2k or so on a 157k Rodeo - we never even thought of trading it though, runs too good with actually fairly little issues, with the exception of some parts that had to be replaced just this last year.

Hate to say this though, the power in the 4.0L X, puts the 3.2L to shame; course there's 9yrs difference in age here.

But wow - can I say, ummph!:smokin:

Awesome. I always liked the looks of the xterra & love nissans for that matter. We've had a cpl of sentras over the years, and my inlaws have a 1998 maxima that's been trouble free and still looks new with minimal care. Great engines and transmissions. I *think* nissan uses jatco transmissions which IMO are great. ATF dipstick AND a drain plug! Gotta love it.

Joel