Initally I had a SES light for p0505 (IACV malfunction) although my idle seemed normal. Instead of immediately replacing the entire IACV unit, I decided to take it appart and clean it. I cleaned every moving part inside the IACV, as well as the throttle body (being careful not to get TB cleaner inside the TPS). After reinstalling everything, my idle jumped to a constant 1,500 RPM in park and neutral, 900 RPM in drive. I performed the Idle Air Volume Learning procedure a few times to no avail.

I have searched many threads but they all seem to end with no conclusive answer as to what the bottom line issue with this problem actually is. Some people seem to think that the faulty IACV blows the ECM, and others spend hundreds of dollars replacing throttle bodies, MAF's, IACV's... Is there anything else I can try besides having the dealer perform a CONSULT-II idle relearn? I'm still getting a SES code for the IACV, but the light doesn't come on during driving, only when idling at 1500 RPM for sometime. Before I cleaned the IACV the light would come back on immediately after I reset the ECM (so I'm guessing cleaning the IACV helped in some way but the high idle is still triggering the SES light blaming it on the IACV).

PLEASE HELP!

 

Well this is my experience with the IACV on the 5th Gen. Maxima.

There is a stepper motor on the assembly that goes bad. That is why no amount of cleaning or adjustment will fix an old valve. It is true that a malfunction of this little motor can cause the ECU to damaged. I would recommend that you repalce the entire assembly and start over.

 

Any reason why the stepper motor can't be purchased on its own?

 

first: did u disconnect the TPS from the TB, if so thats most likely ur problem. it needs to be set to .5 Volts or as close as possible (idealy to original possition even its thats not .5V....u should make a mark before taking apart if u havent taken it apart yet)

second: try to perform the idle relearn byt the dealer with consult 2, even that doesnt work a lot of the time and idle will just go back to what it was when u start the car next time (as happened like 3 times with me).

lastly, u may want to invest in a new iacv if u nothin else works. its $200 from Dave B.

our TB/IACV/TPS assemblies are not to be messed with, ive had so may idle problems since cleaning it the first time, ive heard lot of other people with same problems. my idle is still f'd up, idles at like 550 most of the time, sometimes dies on starts.

 

Nope, I made sure not to touch the TPS. Did not remove it.
What did they charge you to do this?
I'm willing to buy the part but I'm worried that the idle will be 1500 rpm yet again after the install and that perhaps my ECM is fried. Should I not be worried about this?

 

I am experiencing the exact same problem right now. Does your IACV motor make a weird and excessively loud noise when you first take off after starting? It only happened after I cleaned mine.

 

If your car is under 90k or you can get your ECM replaced under the Federal Emissions Warranty. If you're over 90k then it'll cost you about $1000 w/labor.

My brother's car had the same code pulled. When the tech removed the ECM he heard parts rattling around inside. He decided to take the ECM apart and found a blown circuit (or whatever the technical part is called), literally blown to pieces. After the new ECM was installed the code disappeared along with the high idle. Along with that he had to reprogram the keys.

*edit* This was after he replaced the TPS and the IACV.

Hope this helps.

 

Yes, your post was the one that I was referring to when I mentioned a blown ECM. I'm really hoping it's not the ECM because I'm at 98k. Can I still get the ECM under warranty not including labor? I do everything myself anyway.

 

No s***. Call a junk yard and get an ECM. All you have to do is plug and play then reprogram keys. Sorry,I'm not paying 1000.00 to anyone unless they swallow all night.

 

What's "reprogram keys" mean?

 

Monty31,
Same problem exactly.
I replaced the IACV, it changed nothing.
I messed with the TPS and only made it worse.
My idle is 1500+ and my drive is 900rpm and as soon as I release the brakes my car just takes off.

Brought it to my mechanic, he could not do anything.
He says its most likly the ECM.

car-part.com has our ecm from 75-350. Best way is to find your ecm and take the exact model of it down. When calling the junk yards from car-part.com be sure to give them that model number so they match a computer to your car.

hope that helps as i am in the process of doing it too.

 

if u come up to one of the techs and slip him a 20 im sure theyll do it for you.


about this i dont know, i guess its worth a try. i think if ur iacv makes noise when u start the car and shut it off it means the little motor inside is working. it may be worth to spend the 200 for a new iacv, i really dont know. i do hear lots of guys here having problems with ECM weather they changed iacv or not. i also herd some say if u change the iacv u may need a new ECM. i changed my iacv and everything else works fine, so i guess thats not true.
these idle problems are getting to me as well, nissan certaily fuked up here.

 

Hey guys, I've been thrue this 2 times already, the first time the dealer blows the ECM and the new IACV, they replace everything under warranty.

Six months later guess what ? same thing again, they replace both the ECM and IACV. Now a year a half later guess what again, the IACV goes bad again, but this time I only purchase a new IACV from Summit since the car is no longer under warranty. I'll be replacing the IACV today or tommorow, I was suggested to unplug the battery before replacing the IACV and perhaps the ECM need to be flashed but I'm going to try to just replace the IACV and see what happend. When for the third time the IACV went bad I decided to keep driving the car that way for a while, to my surprise the cel just went by itself and I no longer have the rpm jumping from 600-700 rpm to 1800 but my idle is too low. Now everytime I start the engine if I dont give sa little gas the engine die when I re-start the engine it's running fine except the low idle.

 

Can anyone tell me where the ECM is located in a 2k1 ?

Thanks for your help.

 

I believe the ECM is behind the glove box.
Too bad your too far away we could of tried to solve the problem together since mine is identical to yours.

 

How funny, i'm having the same exact issue, i'm going to the dealer tomorrow to do the idle relearn and hopefully it will work, Redline and I have tried just about everything up to this point....if not i'll be looking info my options from there (ecu replacement, engine swap, etc.)

 

Is there any way that consult II can tell me if my ECM is bad? Or do I actually have to remove the ECM and have an expert take a look inside of it?
Is your SES light on as well? Please let me know if the relearn works out for you and whatever else you find out. Thanks.

 

yeap, sure is & i'm getting the code for the IACV. I'll keep you all posted and let you know what I find out tomorrow.

 

The car keys have to be reprogrammed to match the new ECU. That's why it costs so much if you lose a key to get a new one.


You don't need to remove the ECM to tell. If you get the p0505 code that is most likely a fried ECM.

 

Have exact same problem. I've cleaned TB butterfly the other day it seem to improve situation a bit. still have to accel. until engine worms up.

Well has anyone solved this problem?