2002 Pathfinder wont idle - Any suggestions?

[Buzzman]

Great news that you were able to fix it - let us know if the idle relearn procedure gets everything in spec.

Will do.

[01silvapathy]

Okay so I have had my truck parked for about a month an a half with this code. And of course during that time my daily decided to act up too so obviously I put my money into the car that gets triple (literally) the mpg. So now I think im safe to put some money in the truck. My main questions are as follows

-Did you replace the supid phillips head screws with hex bolts when you re attached the IACV? All my screws stripped in the process of getting them out....idk why nissan engineers thought it was a good idea to use them

-I know this is a dumb question but where is the ECM located? I figure ill pull that now and get it sent out so its a quicker process

- Did you look at the bottom of your throttle body before you re attached the new IACV? Mine seems to be destroyed/disintegrated by coolant....now im wondering if I need a new throttle body. Ill try and snap a pic later

[Buzzman]

Okay so I have had my truck parked for about a month an a half with this code. And of course during that time my daily decided to act up too so obviously I put my money into the car that gets triple (literally) the mpg. So now I think im safe to put some money in the truck. My main questions are as follows

-Did you replace the supid phillips head screws with hex bolts when you re attached the IACV? All my screws stripped in the process of getting them out....idk why nissan engineers thought it was a good idea to use them

-I know this is a dumb question but where is the ECM located? I figure ill pull that now and get it sent out so its a quicker process

- Did you look at the bottom of your throttle body before you re attached the new IACV? Mine seems to be destroyed/disintegrated by coolant....now im wondering if I need a new throttle body. Ill try and snap a pic later

Ok, I'll try and answer your questions, having gone through this personally.

When I replaced the IACV, I also replaced the bottom section that the IACV bolts onto.
That section is the part of the throttle assembly that can be removed/separated by taking out five Phillips head Screws/bolts.
The IACV was about $400 from the dealer, and the bottom section, with gasket and new screws, was only an additional $20.00.
That section is what the coolant runs through. The rubber gasket keeps the coolant from leaking.
Trust me: Spend the extra $20.00.
Hope this pic helps:


The ECM was a bit of a pain to remove, only because other wiring harnesses get in the way.
The ECM is located under the dash, to the right of the steering wheel.
You have to remove the lower cover under the steering wheel (the one that has the ash tray and the outside mirror adjustment knob in it).
The ECM has a large (in my case), grey connector on it.
The connector has a lever on it that pulls and locks it in place. Thankfully there are no tabs to push in like on most other connectors.
The unit is held in with a couple of 10MM nuts (bolts? can't remember) on the bottom part.
At the top of the ECM is another funny bracket that somehow fits/slides into a slot that you can't really see. It's a pain, and totally redundant.
When I put the ECM back in, I left that part off, and only installed the two nuts on the bottom. That's all you need.
I didn't take a picture of the ECM under dash. Sorry. It was the middle of winter when I did this, and freezing. My fingers were numb.


Quick edit: had to do the relearn. After the repaired ECM went back in, my idle was too high (close to 1000 RPMs)
The tech at my dealership did the relearn (with his magic scan tool), and presto, she idled and ran perfectly.
The relearn took less than 5 minutes, and he did it for free.

[Greilly]

Question- how similar is this system to the 2001 maxima system? I've been reading a lot of treads about the Maximas having an identical problem and I want to know which of these items apply to the pathfinder/QX4 line:

1. Will busted motor mounts effect the ECM?
2. The coolant that runs through the IACV seems to be shorting out the IACV after time. Some have suggesting bypassing the IACV with the coolant by modding a tube around the IACV and connecting the IACV lines to itself, thus not allowing coolant to flow through the IACV. Is this a solution or a terrible idea after installing a new ECM and new OEM IACV?
3. How important is it to get an OEM IACV?
4. Why did Nissan replace the original IACV (part number: 23781-4W000) with a new one (part number: 23781-4W002)? Do they know the their originally installed IACV is faulty and on the brink of failure? If so, why wasn't there a recall?
5. When fixing the ECM, is it smart to install a chip that prevents overheating by monitoring the IACV signals? Such a chip would pause the signals and prevent the ECM from blowing up (see http://www.avproecm.com/nissan.htm )
6. And finally, who's the incompetent engineer who designed such a crappy system, namely the person who failed to put a safety mechanism on this path of the ECM? Walmart vacuums have better failsafes than my $40k vehicle...

[Greilly]

Update:
Installed OEM IACV and rebuilt ECM from Digital auto technologies in Riverside, CA. Upon first startup, engine revved extremely high during idle while warming up (2250rpm). Once warm, throttle was autonomously engaged and disengaged multiple times per second which caused the rpm gage to jump between 2250 and 2500 very quickly. When put into drive, idle was still high at about 1250 rpm. I would have no pressure on the execrator and shift into second gear with ease.
Checked TPS, made small adjustment, fired the truck up again. Same story with the jumping rpms but this time it was between 1500 to 1750. During this whole time, I couldn't get the idle re-learn procedure to take. Frustrated and in disbelief, I unplugged the battery, and let the ECM reset itself overnight.
Got up the next morning, truck fired up to 1500 rpms and slowly dropped to around 900 and held steadily. shifted into gear, drove around 30 miles and everything seemed to work fine. rpms still high on idle in park, but right on the dot at 750 when in drive.
Truck is shifting hard into second gear, so I'm going to do a tune up and make sure the fluids are clean. Any comments or tips to finish this repair correctly would be appreciated.

Video 1: https://www.youtube.com/watch?v=YnnLuXI ... 04X2qDTHCQ
Video 2: https://www.youtube.com/watch?v=qKV-tP2 ... e=youtu.be

[Towncivilian]

The transmission may shift hard for a little while until the TCM "relearns" your driving style - it forgot it after you disconnected the battery.

You followed the idle relearn procedure described on page EC-57 of the factory service manual to the letter, correct?

[Leo1998]

@Towncivilian...Do you know if the '98 Pathfinder has a Idle/air relearn procedure or is it for the 3.5L engines and up only? I was in the EC section of the FSM and didn't see anything for it.

[Buzzman]

@ Greilly: After changing the IACV and repairing the ECM, a relearn is definitely required.
After I did my IACV, it idled at around 1000 RPM's, and generated a fault code and CEL for (you guessed it) idle too high.
I tried and tried to do the relearn as per the FSM, but it never "took".
Not sure what I was doing wrong, but I followed the procedure to the letter, and it still wouldn't work.
I stopped by the dealership, where I know one of the techs really well.
He hooked up his scan tool and did the relearn for me. Took 5 minutes....no charge.
Idles perfectly since, and no more CEL.

[Towncivilian]

@Towncivilian...Do you know if the '98 Pathfinder has a Idle/air relearn procedure or is it for the 3.5L engines and up only? I was in the EC section of the FSM and didn't see anything for it.

VG33E Pathfinders have no relearn procedures of any sort.

[willy0505]

Hey guys - posted a new topic on something similar - but when you replaced the ECM, is it essentially plug and play or do have to go to the dealership to have the ECM reprogrammed?

[Buzzman]

If it's your old ECM that was just repaired for the IACV problem, then it's plug and play.
The only thing to do there is the idle relearn.

If it's a new ECM, or an ECM from another truck, then you'll have some programming to do,
like the key FOB for example.

[Johnnypath]

Just had the smoke from steering column from my 2001 PF and yes electronics component burnt. Idle Air control valve shorted out ECM as above. I have a spare ECM from 2002 PF from wreckers.

Q1. If I get new IACV, would I be able to use 2002 ecm (if in good condition) and what would be required to get it to recognize my key?

Q2. Can you just buy IACV motor which I would assume to be much cheaper than buying whole valve assembly ?

Q3. Anybody had any success in soldering in replacement component in ECM?

Sorry can't bring this to dealer as I'm sure repair will cost me more than car did.
Thanks in advance and great posts.

[Bimmer-Adict]

I am having the same problem with my 02 QX4, six months ago I paid 2K for it with 150K running and looking great. Now I need to do the IAC and ECU and I am sure that the dealer will charge about 1800 to 2K for the repair . The price they quoted me was IAC $325 and ECU about 1$1200 plus labor. I am now wondering if its worth it or cut my losses and junk it. Must admit it drives great and body great no major dents or scratches. I heard that I can get the ECU rebuilt for about 2 to 300 . Let's see which way it goes.

[4xq]

JohnnyPath- I looked at car-part.com and it does not look like those ECM's interchange. They show all ECM's by model year only. You may want to call your wrecking yard to verify that tho. They should be able to tell you exact interchange info. Looks like part numbers need to be a match.

To use a replacement ECM, you need to get it reprogrammed to your key. Dealer prices vary.

I do not believe you can just buy the IACV motor. I actually looked for that on Ebay, it was a no-go. Whole assembly only, unfortunately.

Yes, people have repaired their own ECM's. You need some soldering skill - but it doesn't appear to be that difficult, altho I have not done it. I thought I had saved the chip ID, but I am not finding it right now. Maybe someone else knows it.

Also, there are the ECM repairs on Ebay - lowest price is 82.00 I think. Hope that helps!

[4xq]

Bimmer-Adict, there are the ECM repairs listed on EBay - one of the places is now at 82.00. New IACV is 125.00 to 200.00 aftermarket if you shop a little.

No need to use the dealer on a car of this age - just find a shop that knows Nissans. That should save some cash.

[Buzzman]

I am having the same problem with my 02 QX4, six months ago I paid 2K for it with 150K running and looking great. Now I need to do the IAC and ECU and I am sure that the dealer will charge about 1800 to 2K for the repair . The price they quoted me was IAC $325 and ECU about $1200 plus labor. I am now wondering if its worth it or cut my losses and junk it. Must admit it drives great and body great no major dents or scratches. I heard that I can get the ECU rebuilt for about 2 to 300 . Let's see which way it goes.

Check out the entire thread. Do not fall into the dealer trap and get sucked into paying $1,200 for an ECM.
There are companies out there that rebuild them for exactly this problem (IACV burnout).
If the truck is as nice as you say, then it's worth replacing the IACV and repairing the ECM.

[Johnnypath]

Ok my plan is to:

a: do ohm readings on 2002 ecm for all connection points to chip then on my 2001.
b. remove chips from 2002 and 2001 ecm and again do ohm tests.
c. if ohm readings close install chip from 2002 into 2001! If not junk pathfinder.
d: order new valve
e: test ohms on new valve
f: install and start with relearn procedure
g: have a couple beers and post what i learn.

To anybody out there who has an old pathfinder and would like to keep it, I would recommend getting new iacv before ecm is fried!

Thanks

[fastpakr]

Ok my plan is to:

a: do ohm readings on 2002 ecm for all connection points to chip then on my 2001.
b. remove chips from 2002 and 2001 ecm and again do ohm tests.
c. if ohm readings close install chip from 2002 into 2001! If not junk pathfinder.

Did you look at Circuit Board Medics? They can repair your ECM.
http://circuitboardmedics.com/2000-2003 ... cm-repair/

[Buzzman]

Did you look at Circuit Board Medics? They can repair your ECM.
http://circuitboardmedics.com/2000-2003 ... cm-repair/

That's who did mine. Good service and fast turnaround time.
$250.00 flat rate.

[4xq]

For the record here, I believe the IC chip that fails is a sanken sta509a. They can be purchased on Ebay for under 10.00.

Johnnypath, you should be able to pull the cover off of the 2002 ECM module and check to be sure that is correct.

[shawnsnico]

Thougth I would post here on a similar problem I had wiith a low idle issue on my 2003 pathfinder. It was slightly different in that my issue was consistent - the car would start fine when cold but whenever it warmed up I would have to take it out of drive when I came to a stop or the RPMs would drop below 500 and occaionaly stall. I would also have to rev it to restart when warm. I had tried a tune up, replacing all the vacuum lines and cleaning the throttle body with carb cleaner - no luck.

I had resigned myself to just living with the minor annnoyance but I was looking for an oil leak this past weekend and decided to pull the throttle body and try a foaming throttle body cleaner I had bought for a volvo rough idle issue. I applied it several times and let sit for awhile after each application before cleaning, making sure I got rid of all residue on the points where the valve stem entered the TB housing. Put it back together and my low idle problem is gone!

As a side note I did gently manipulate the TB valve during the cleaning without apparent problems. I have seen some threads warning against this.