# 2k1 Idle going crazy + loud intake



## slobo430 (Jan 7, 2006)

Hello all,

I've read about a thousand posts on couple of forums in past couple of days and have found few people with similar symptoms but mine are a bit different. I've had my 2001 max for about 6 months and it has about 45k miles on it, pretty good care. 2 Nights ago I was driving and I noticed that when I was at stop light my idle was quiet high but I didnt think much of it...on my way back home when I started it, it barely turned over, seemed very week and idle was compleltley irregular [it was quiet cold and I've read tons about cold starts]

However tonight the problem got a lot worse. After driving the car during the day time without any problems, I went out in the evening to turn it on and all hell broke loose. The air-intake seems to be drastically louder than ever before and my idle is at about 2 constaltly jumping to 2.5 and back down in very very rapid intervals, as if I was stepping on and off the pedal to rev the enging up so its constalty going wroom wrooom wrooom wrooom and the intake seems extremely loud. The Service Engine Light came on as well :-( .

I know if I take it to the dealer I'll get a list of all bunch of stuff to be changed from o2 sensors to bad fuel pump or fuel filter, bad mass air flow meter or bad intake gaskets, or intake leak but I wanted to see if anybody here has had solutions to problem like this, rather than getting tons of stuff changed that doesnt need to be.


Thanks a ton in advance!


----------



## Captain Obvious (Jan 2, 2004)

this may sound kinda simple but I had the same prob on my ford escort

look in your air box and check the air filter 
mine actually broke up cause it was wet outside and the plastic part came loose and lodges itself in the intake tube and was starving the engine 

changed the filter and all was good 
try the simplest thing first 
at 45k you shouldnt need new o2 sensors or temp sensors or anything like that 
make sure that the intake is on tight and nothing obstructing it other than that I dunno I hope some one else here can help


----------



## Puppetmaster (Mar 28, 2005)

Since your CEL is on, go to Autozone or anyplace with a free scanning tool to get those codes pulled and post em up here as well.


----------



## slobo430 (Jan 7, 2006)

Thanks a lot for the responses guys, I just got back from Autozone and was reading the posts, the codes came back as P0505 - Idle Air Control Valve / Auxiliary Air Control Valve which is what I thought the problem was initialy. I'm gonna do a few more checks before I actually go ahead and order the new piece but what would cause this? Its kind of funny that it hapened the same night I had installed my new xm radio system..... I know theres nothing really that I could have touched behind the dash that could have caused this problem but you never know.

I'm also not running the stock airbox, I have a full intake system running to it but I'll doublcecheck the pipes and filteritself.


----------



## smj999smj (Jan 1, 2006)

You may also want to check the upper plenum gasket. Nissan updated the original gasket to promote better sealing. Spray a little carb cleaner around it while it's running and see if there's a change in the way it runs as you spray.


----------



## zooropa (Jan 11, 2006)

just wondering if you've changed the Idle Air Control Valve yet? I changed mine after I had that code, the code still pops up. 0505. I'm thinking I'll try to change the throttle body, (I tryed cleaning it twice, it is very clean). Also, I started getting that code after I changed the stereo. !!!????!!!


----------



## DRUNKHORSE (Mar 6, 2005)

A P0505 code means that there is no failure. atleast no OBD system failure.


----------



## zooropa (Jan 11, 2006)

that's an idle air control code for the 2000 maxima...OBD II


----------



## zooropa (Jan 11, 2006)

http://www.obdii.com/codes.html


----------



## Puppetmaster (Mar 28, 2005)

The possible causes of that code are the IACV-AAC circuit being open or shorted, the air control valve (power steering), and the IACV-AACV itself, according to the 2001 FSM. 

Check all the wiring (connecors and harnesses) to make sure nothing is broken or shorted before moving on to replacing parts.


----------



## slobo430 (Jan 7, 2006)

Puppetmaster said:


> The possible causes of that code are the IACV-AAC circuit being open or shorted, the air control valve (power steering), and the IACV-AACV itself, according to the 2001 FSM.
> 
> Check all the wiring (connecors and harnesses) to make sure nothing is broken or shorted before moving on to replacing parts.


You're completley right, the IACV somehow got stuck open and caused a short curcuit on the computer controlling it and fried it, so I had to replace the whole computer underneath the steering dash....dealership wanted 700$ for the new CPU part, but I went to junkyard and found a identical 2001 and ripped it out for $140 out of there and just had the nissan guys do a quick repogram and replaced the IACV valve and its back to runing perfectly.


----------



## zooropa (Jan 11, 2006)

so you had the whole ecm replaced?


----------



## DRUNKHORSE (Mar 6, 2005)

zooropa said:


> so you had the whole ecm replaced?


read my friend...




slobo430 said:


> You're completley right, the IACV somehow got stuck open and caused a short curcuit on the computer controlling it and fried it, *so I had to replace the whole computer underneath the steering dash....*dealership wanted 700$ for the new CPU part, but I went to junkyard and found a identical 2001 and ripped it out for $140 out of there and just had the nissan guys do a quick repogram and replaced the IACV valve and its back to runing perfectly.


yes, he did. which means, he now has an extra ECU.


----------



## zooropa (Jan 11, 2006)

read my question...

Alot of people use different terminology for the ecu=ecm=cpu...

Never hurts to confirm things, that's what a forum is for...


----------



## zooropa (Jan 11, 2006)

p.s.

My follow up question is, how did your maxima even run if-

"caused a short curcuit on the computer controlling it and fried it"

I thought if a ecu was fried, the car wont even start...am I wrong?


----------



## slobo430 (Jan 7, 2006)

If someone can shed some light on this it would be much appreciated because thats the same question that I was wondering myself....if a part of the ecu was blown then how was I able to drive the car for the week? I inspected the ecu when I went down to the shop for the visit and saw the fried piece myself but my suspicion was that it got fried during the IACV "fixing" process.


----------



## smj999smj (Jan 1, 2006)

An individual circuit of an ECM can open, or "fry" if you prefer, and not affect other circuits. Depending on which circuit or circuits it is, the ECM may still be able to control the functions required to allow the vehicle to drive.


----------



## slobo430 (Jan 7, 2006)

phew ok thanks just wanted to make sure.

Thanks to everone for the help, hopefully I can return the favor in the future


----------



## zooropa (Jan 11, 2006)

I guess I should pull my ecu out and see if it looks melted or has the burning plastic smell. I'll do that before a throttle body replacement. Thanks!


----------



## zooropa (Jan 11, 2006)

ok, I pulled the ecu, it looked fine, no burned areas. I got a used one from a junkyard for $150. Swapped it out at the dealer's parking lot, had them reprogram it right after for $40. No more code 0505!! It runs great, must of been a bad circuit on the ecu board. I think the IAC valve went bad and burned out the ecu control area also. Thanks for the help!


----------



## slobo430 (Jan 7, 2006)

Yup wish I had done the ecu swap before I bought the brand new IACV but I guess it was only 160


----------



## NissanNewb (Jan 24, 2009)

Question.....

True or not: If you swap out an ECM with either a brand new one or a used one, the car will not be able to start until you reprogram/flash the "new" ECM?

I am having similar trouble as the creator of this post, but I was told yesterday that if I had the ECM replaced, I would have to have the car towed to a Nissan dealership as it would not start up. Not sure if he was correct or not. 

Also, I know there are 2 different ECMs for a 2001 Maxima, automatic:

Without Traction Control 2371M-5Y006RE 
With Traction Control 2371M-5Y016RE 

Here's a silly/stupid question. How do I know if the car has traction control or not? lol


----------



## badchoka (Feb 10, 2009)

I know I'm just a newbie on this site and I still have a lot to learn on the max, but from what I understand of the ECM, since it controls a lot of thing (fuel injection, ignition timing, idle speed, valve control, etc), it has to be program for your car. So getting an other ECM and installing it without reprogramming right away, chances are good that your car won't start or you will experiment starting and driveability issues.
As for the traction control, I have it and it's a button that says 'TCS off',on the right of the steering wheel, look under the temp gauge near the ignition, you should see it if you have it, that's how I knew I had traction control.

I experienced almost the same problem last week, I went to the dealer and they told me that the IAC valve and the ECM were bad. So now, they want 1624$ plus taxes to do the job but I think they're going too far this time. I love my max (SE 2k1) but I experienced a lot of electronic issues over the past 3 years. Now I came to realize that I'm not the only one with that problem, from what I read, when there's an IACV failure, it comes with a fried ECM. That's a pretty good way to make money. Anyways, here in Quebec, I have a hard time finding parts for my car in the junkyards, so I don't really know what to do right now since I don't have that much money right now to put on my car.


----------



## TheRepairMan (Jun 30, 2009)

Old thread but I'm curious as to whether there were any more updates or info on the ECU concerns.

My daughters 01 Maxima SE has started acting up. She says once in a while it cranks but won't start ...the engine turns over but won't fire. That rules out the new Battery, and the Starter obviously is fine, too. I have yet to see it happen so I don't know if it's losing Fuel or Fire. She also says she can turn the key to off and back to crank when this happens and it will usually fire right up.
I haven't had the chance to check the State of tune, Battery cable ends, dirty Throttle Body, etc., but I'll be doing all that soon just to make her feel better. 

I'm thinking the electrical part of the Ignition Switch "may" be starting to go bad ...don't know yet.

Anybody else seen an 01 Maxima act like this?

TIA,
Roger


----------



## nismopheliac69 (Jan 18, 2009)

if the ecm "fries", it could theroretically be only a section of the ecu if im not mistaken. It doesnt necessarily mean that the whole system is junk


----------



## TheRepairMan (Jun 30, 2009)

nismopheliac69 said:


> if the ecm "fries", it could theroretically be only a section of the ecu if im not mistaken. It doesnt necessarily mean that the whole system is junk


That's true, but either way if the ECU has a bad circuit the unit has to be repaired or replaced. There are several places in the US that rebuilds them.

I wasn't trying to highjack the thread, but I wondered if anyone has seen intermittant no start symptoms from either the ECU, or the Main Relay that powers up the ECU and the Fuel Pump.


----------

