2002 Pathfinder wont idle - Any suggestions?

[gatiman]

My 2002 Pathfinder just abruptly shuts of and wont idle when you let of on the accelerator.
Put it in neutral and it cranks fine, revs with no problem, all indications are fine until you let off on the gas, then she stalls and engine quits.
Put it in park and she starts right up, until you let off on the accelerator. I was able to drive her home by keeping light pressure on the brakes ( to keep her from moving forward) and light pressure on the accelerator to "force an idle" with rpm's near 1000.

Any suggestions as to why she wont idle correctly?

[Towncivilian]

No Service Engine Soon light? Make sure the SES bulb works by engaging the parking brake then turning the ignition to the ON position and looking for the light.

Check connection of the IACV (Idle Air Control Valve), the black cylindrical part with a blue plug located under the throttle body:

[gatiman]

SES light functioning OK and doesn't stay on when cranked up and running ( again with light pressure on accelerator pedal).

I cant get to the connector tonight to check connection, but agree that the IACV is bad or the connection may be loose. I will check in the a.m.
Thanks for the quick reply!

If not IACV, any other possibilities?

[Towncivilian]

If it's not too much trouble, try getting codes pulled at an AutoZone or other local parts store that does that for free, or find a friend with a code reader. There may be stored codes which are not triggering a SES light.

I don't know of other specific possibilities. Perhaps check for vacuum leaks, and clean the MAF sensor (will require a tamper-resistant T20 Torx bit and some spray MAF cleaner).

How is your oil level? I'd think that low oil pressure could affect idle, and your artificially high idle would keep it high enough to prevent the engine from stalling. A clogged fuel filter may also lower fuel pressure in the same manner, but I've not read of either condition happening. What is your current mileage?

[gatiman]

I am the sole owner, bought her new in 2002. She has 142,056 miles.
Other than oil changes religiously every 3k miles, tires, brake pads, rotors, fluid changes, plugs, etc. have had no problems ever, been a great SUV.
Oil was changed 2100 miles ago, she has never "burned" oil or been low during change cycles.

Recently had the dealer replace the O2 sensors when the SES came on, haven't seen any problems or codes as of late.

[gatiman]

I am surprised how fast the idle just quit without warning this evening. Everything normal on the commute ride home and then let off on the accelerator and she quit.
It caught me off guard, quickly shifted into neutral and tried to crank he before power steering stiffened up.

BTW the O2 sensors were replaced this time last year.


Thanks for your help Towncivilian!

[Towncivilian]

Try following the idle air volume relearn procedure as detailed on page EC-71 of the FSM.

[asnorton44]

My guess is MAF I was having the same problems.

[ARKQX33V6]

At your mileage test your EGR, have you ever cleaned your throttle valve and opening. When cold does the engine fast idle, could be the coolant sensor.

[philcoke]

Did you find out what the issue was? My 2002 Pathfinder is doing the exact same thing. I tweeked the idle to stop it from stalling and runs ok, but still won't idle at start up with out giving it gas.

[asnorton44]

Try disconnecting the MAF and see if it idles.

[fastpakr]

I apologize for bumping an older thread, but this appears to be precisely what I'm experiencing with an '01. Issue started a week or so ago, two days after picking it back up from a shop for a tune up. At the same time the MAF was also replaced. Truck ran great for a couple of days, then suddenly stopped controlling the idle. With the engine warmed up it began to shut off every time I came to a stop. No problem starting back up immediately, just had to use the accelerator to keep it running.

I took it back to the shop and they performed an idle relearn which seemed to fix the issue for another couple of days, but the issue recurred this morning. However, it ran fine an hour later when I drove it to the shop to look at it again. No other noticeable symptoms. Power is fine, truck runs great aside from the idle problem. SEL has not come on either time it's acted up.

Anybody else run into this issue and chase down the culprit?

[gatiman]

I ended up having to replace the ECU board and this fixed the problem, sold the car for a new 2012 pathfinder and no more problems.

[Towncivilian]

What brand MAF was used as a replacement?

You can try disconnecting the battery to reset the system and then performing idle air volume relearning yourself following the steps on page EC-71 of the factory service manual.

[fastpakr]

Not sure about brand, but based on prior experience with these guys it's almost certainly an OEM unit.

I believe they did an idle air volume relearn the first time I went back in. Whatever they did caused it to run perfectly again for a couple of days.

The SES light actually came on this morning while driving. I'll try to run the codes this evening to see what comes up.

Thanks for all the tips.

[kjbftbll17]

It looks like I am having the same problem now. Replaced the IAC valve and did the idle relearn. Seems to work for the initial test drive, but then fails on subsequent attempts. The mechanic is recommending a new ECM. Did this solve your problem? If so, are there any other concerns as far as needing to replace the throttle position sensor or having to do anything with the anti-theft system? The mechanic said both are "recommended". I wouldn't think a new TPS would be required. As for the anti-theft system, I have no idea. I didn't even know I had a chip key. He's concerned that since the anti-theft circuits (don't know the correct terminology) are integral to the ECM, getting a new one would require some kind of relearn/reprogramming/... more money.

Thanks!

[fastpakr]

Mine did require an ecm replacement. There are some companies that offer repair service.

[Buzzman]

I've been having this exact same problem for the last two months.
Have not been able to fix it yet. There is no SES light or fault codes.
I've tried 3 different MAF sensors, and replaced the entire throttle body assembly, with no luck. Same old thing.
I rigged the throttle home position with a ty-rap to keep the revs up so that it doesn't stall when warm.
It still won't start and idle when it's cold. I have to keep my foot on the gas pedal until it warms up.
My mileage has also gone down the s*** as a result.
I've set up an appointment at the dealership for next Tuesday.
They have one mechanic there that I've known for 25 years, and is the only guy I trust.
He said he'd check it out for me and let me know what he finds.
I'll post the findings on here next week.

There is mention of the ECM going bad on this thread.
Maybe Town can answer this question for me: will an ECM from a 2001 work in a 2002?
I can probably pull one from a wrecked 2001at my local junkyard.

Thanks everyone.

[Towncivilian]

There is mention of the ECM going bad on this thread.
Maybe Town can answer this question for me: will an ECM from a 2001 work in a 2002?
I can probably pull one from a wrecked 2001at my local junkyard.

"Probably", but no guarantees. 2002 isn't drive-by-wire still, so it's possible it would work fine. On the other hand, there may be programming differences which could cause issues. In short, it's trial-and-error - hopefully you can source the junkyard part for cheap, otherwise I wouldn't chance it.

[Buzzman]

Thanks for the quick reply Mr. Town. Awesome moderator BTW. Keep up the good work.
Also: I get the drift that you are in Florida?
My wife and I are planning to escape the Great White North for a few weeks later this month.
It's just too cold up here, and we hate the winters. (It was -15F earlier this week.)
We plan to drive to Florida and meet up with some friends, and do some exploring at the same time.
What part of Florida are you located? What do you recommend?
We'll be going to Singer Island for a few days, among other places.
Cheers.

[AceEngineer]

A bad IAC took out my ECM. These guys repaired it: http://circuitboardmedics.com/infiniti/ Cheaper than a new one.

AceEngineer

[Buzzman]

Well, after 10 years of fault free ownership, it looks like I've finally been bitten.
The verdict from the dealership is that the problem is a bad AICV, and a bad ECM. Which one took out the other is up for debate.
I left the dealership with my truck un-repaired.
The ECM is $1000.00, and the valve is $450.00. No way I'm paying that.
They said they could get a rebuilt ECM for half the price, but with no warranty. Not sure about that.
The tech adjusted the throttle cable so that the truck will idle without having to keep my foot on the gas. Nice touch.
I'm heading to Florida in a few weeks, so I'm going to check out U.S. pricing, and maybe a wrecking yard or two along the way.
Any other suggestions would be welcome.
Thanks.

Edit: Where is the ECM located, and how difficult is it to replace?

[fastpakr]

I'll try to post a link later but there are repair services that will open your ecm and relaxed any blown components and return it with a warranty. As I recall its a one day turnaround for about $300.

[Buzzman]

Update: Contacted Circuit Board Medics, and they were quick to respond.
Turns out they are in South Carolina, and I'll be driving through there next week on my way to Florida.
(We needed to get out of the cold Canadian winter).
I took the ECM out of the truck today (not that easy, and I froze my a$$ off), and will be taking it with me.
I plan to drop it off on my way down, and pick it up on my way back.
I'll be buying a new IACV as well. Cheaper in the U.S. than in Canada.
BTW, checking a few more sites, I found out that a bad IACV blowing the ECM is not that uncommon.
One site had a warning in big black letters, do not to replace the ECM without replacing the IACV. Good to know.

Oh, I took the covers off of the ECM module and had a look at the circuit board.
No obvious faults or burned out components. Physically, it looks just fine.

I'll update again in a few weeks when I get back and install the new parts.

[Towncivilian]

Sorry I didn't reply earlier. I'm on the east coast of Florida, about half an hour north of West Palm. Be aware that nobody can drive around here, on either coast. Singer Island sure is nice, just don't speed around there - rich area, I'm sure there are many cops waiting to pull just about anybody over.

Bad solder joints on a circuit board can be difficult to spot. Are there any electrolytic capacitors on the ECM? I am just curious.

Good luck with the ECM repair, drive safely, and enjoy your trip!

[Mark Mellott]

I have a 2002 Pathfinder SE as well. Just bought it used in excellent condition but detailed everything possible so that it ran its best. After I ran out of details to check, maintainance, or replace, the idle was a bit too high. The only thing adjustable on the entire emmissions amd engine control systems is the throttle position sensor. I tested it and found that it was good but it was no longer set correctly. There are two screws that hold it in place. When these screws are loosened, the TPS can be rotated a bit back and forth within the confines of the screw slots. This is the adjustment range and it needs to be set to within a .oo4". Check out a repair manual which describes the TPS adjustment procedure. I'm only guessing but since mine was clocked to far one way which made the idle too high yours may have moved too far the other way which will make the idle too slow and stall. I adjusted my TPS to the specifications indicated in the repair manual and then performed an idle air volume relearn prodedure. (part of the Idle Air Control valve section in the repair manual. This is a very important step. After I was done the idle was right at 750rpm. Before doing any of this, be sure to check of any loose or cracked vaccum hoses which are quite often the cause of sudden idle failure you described. Best of luck to you.

[Buzzman]

Sorry I didn't reply earlier. I'm on the east coast of Florida, about half an hour north of West Palm. Be aware that nobody can drive around here, on either coast. Singer Island sure is nice, just don't speed around there - rich area, I'm sure there are many cops waiting to pull just about anybody over.

Bad solder joints on a circuit board can be difficult to spot. Are there any electrolytic capacitors on the ECM? I am just curious.

Good luck with the ECM repair, drive safely, and enjoy your trip!

Arrived at Singer Island yesterday. Crappy drive getting here. Cold, wet, icy, snowy.
You are right about the drivers here. Seen some pretty bad stuff already.
Went to a local Nissan dealership today and ordered the IACV assembly. Still expensive, but cheaper than in Canada.
My ECM is in South Carolina at the circuit board medics shop. Should be fixed this week.
Hopefully in another two weeks when I get home I'll have a running Pathfinder again. It's been a hassle for sure.
I'll keep everyone posted later when I have something to report.
Cheers.

[Buzzman]

Well, tonight's the night.
Got back from the U.S. this weekend. Picked up a new IACV assembly at a dealership in Florida.
Still expensive, but cheaper than here in Canada.
Also got back my repaired ECM from Circuit Board Medics, and will be installing everything tonight.
Fingers crossed.

[Buzzman]

Update: Truck is running again.
Installed the new IACV and the repaired ECM, and everything worked great.
BTW, the ECM came back from Circuit Board Medics with a warning label saying: replace the IACV before installing, or the warranty will be void. OK then.
The idle is a little high at the moment (900 rpms), but I still have to do the relearn procedure.
The good news is the idle is rock steady. No wavering.
All in all, a good experience with the Circuit Board Medics folks.
I e-mailed them several times, and they always responded within hours. Very good service.
One more thing, If anyone has this problem, I highly recommend installing a new IACV, and not a used one from a wrecker or eBay.
It may be more expensive, but I wouldn't take a chance on blowing an ECM by installing a used IACV that you know nothing about.
Cheers.

[Towncivilian]

Great news that you were able to fix it - let us know if the idle relearn procedure gets everything in spec. Thanks for sharing your experiences!