300ZX TT

i have a 2001 Maxima GLE with 55k miles on it and the car is bone stock...i have codes p0100 (MAF) and p0505 (idle air control valve control circuit)

when i start the car, it will start for a second, then it will die....however if i start the car and give it throttle at the same time, the car will stay on as long as i stay on the throttle...but if i come to a stop sign and brake, the car will idle really low and then just die...but i even drove the car as long as i kept the idle up, the car drives ok...it is the same problem this guy is having

http://forums.maxima.org/5th-generat...g-problem.html


before i start replacing things, i'm trying to get a handle on this problem...i'm hoping some of you tech guys can chime in...i've been searching/reading that a bad IACV can short the ecu...i also read that this might be covered under the 8 year 80,000 mile warranty (although i may not be eligible for this?)...i also read that replacing the MAF will require (or is recommended) a reprogramming of the ecu

what should i do first? replace the IACV? MAF? is it likely that only one of them is bad? should i take the car to the dealer and be prepared for a raping? i just don't want to replace things that don't need to be replaced...and honestly, i'm a little confused as to what is going on and what i should do...i would really appreciate some advice

hi-tek22

iTrader: (4)

I had the same problem, AS YOU KNOW

NEW MAF fixed the P0100, you can try cleaning it temporarily, but it will only put a band aid on it...it will temporarily fix the problem and more than likely come back

AS FAR AS THE IACV.... I think a new one is the only thing that will resolve this...the IACV is inside the throttle body. I had coolant leak inside my throttle body because mine was leaking anti freeze, and FRIED my IACV, not to mention the buttertfly valve on mine kept making all kinds of noise...so i chalked it up and let the dealership screw me over and put a new one on...including the IACV that i purcahsed brand new from Dave B

CHECK OUT MY THREAD I MADE LAST WEEK, good deal referencing it, lol

AT THE END.....THE BAD IACV did short out my ECU because the leaking coolant killed both my IACV, and the ECU....(according to the dealership), and i had that replaced, along with the throttle body, and THE IACV i purchased....TOTAL COST 2,000 bux out of pocket *OUCH*

300ZX TT

do you think your MAF had anything to do with it at all then? or do you think the IACV is the problem? i don't want needlessly replace things...i guess what i'm asking is that if a bad IACV can cause the MAF P0100 code?

visually, i don't see any kind of coolant leak or anything around the throttle body...i really freakin hope the ECU is okay...did you ask them if this was covered under any warranty?

hi-tek22

iTrader: (4)

nah I think my maf was slowly DYING on me anyway, I noticed it would lag on me sometimes...I had cleaned the MAF and it stopped lagging, but i went ahead and replaced it as one of the 1st things i tried

as far as any warranty...LOL, I WISH...my car has 111,300 miles n it.

as far as the work the STEALERSHIP did...they warranty the work for up to 12 months/12,000 miles....which ever comes first...Ive been driving pretty hard the last couple days to get the ECU to learn my driving habit, and so far so good....

300ZX TT

can anyone explain the warranty to me a little bit more? maybe i'm searching the wrong things...could it apply in my situation?

i guess i'm screwed and i'm going to take the car to the dealer unless someone can advise me otherwise?

oldngivout

iTrader: (8)

Actually it is the stepper motor on the IACV that shorts out and fries the ECU.
It can happen with no visual signs or warning.

300ZX TT

i see

so, is going to the stealership to let them diagnose it the best thing? i'm trying to avoid going there if possible, unless someone can provide me alternative?

i can change the MAF and IACV on my own if necessary, but i'd rather not mess with the ECU myself...i just don't want to replace them myself, then have the dealership give me some BS about them needing to replace them again or something (which wouldn't surprise me the least bit)

hi-tek22

iTrader: (4)

Unless you can find or know someone who is damned good with Nissan Cars, then the STEALERship is probably the best bet....Sorry..... (Believe me, I KNOW HOW U FEEL)

I had 2 shops and three mechanics look at my car, and they all made suggestions...at the end of the day i was tired of playing guesswork, so....ergo i made my trip to the stealership

300ZX TT

thanks...i guess i'll be heading there in a day or two...i just hope it's the ecu is okay...i will def post an update in this post after i get this job completed

themaniam1

How do you know if your ECU is fried? My 01 maxima just threw the p0505 code yesterday. Can I just replace the IAVC and not worry about anything else?

300ZX TT

well here is my update for everyone who may search this problem in the future:

I went to Woodfield Nissan out here in the suburbs of Chicago to get a diagnosis done (although i knew what codes i had)...the dealer came back with the same codes, the MAF and IACV...and the lady informed me that my ECU shorted out as a result (i still don't understand why this happens, and she couldn't explain it either)...

as i was about to bring up the 8 year/80,000 mile federal law she tells me that normally this would be covered if the ECU was the problem...but she tells me since the IACV caused the ECU to short, they are not technically liable under the 8 year/80,000 mile law (and i read about this before going there so i knew she was right)...then she says "i'm gonna help you out and we're gonna cover the cost of the new ECU for you anyways if you decide to do all this"...i was thinking "SWEEEET!", but i can't help but think why they would offer to cover the ECU for me? she showed me that a new ECU was over $1,200, not including labor to put it in...while i'm very grateful she did this for me, i don't understand why? were they just trying to get my business? or was it covered anyway, and she made it sound like she was doing me a favor? i didn't want to ask her right then, i'll ask her after all the work is done and i get the car back...so if you have this problem and codes, MAKE SURE you ask about the warranty and put up a fight if they refuse

so the new ECU and the labor to put it in is free...they charged me $146 for a new MAF, and $435 for a new IACV (this seems a bit high)...and the labor to install the MAF and IACV is $550! talk about a ripoff on the labor, i could easily install this stuff myself...but she made it a point to tell me that they would not cover the ECU unless i got the other stuff done there, which is expected...sounds like they may have wanted my business...anyway, my total is $1,206 and they also gave me a free rental (2006 Maxima)

considering it should have cost me double this, i'm okay with it (as much as i can be)...i just bought this car 5 months ago and it's in spectacular shape, and only has 55k miles...hopefully i won't run into any other problems like this...but to me it seems odd that this IACV causes the ecu to short out, why does it happen so much? maybe an engineering defect?

i don't know how the dealer can tell if the ECU is shorted out...but if you can determine that on your own, you could prob do this job yourself...i'm good with mechanical stuff, but not electrical so i didn't wanna attempt this on my own...

i hope this helps someone else

hi-tek22

iTrader: (4)

^^I also wondered how they could tell whether the ECU was shorted out...THEY COULDNT.

I figure if you add the cost of installing a new throttle body at the dealership you would have paid what i paid.....Either way you look at it, its a rip off..........LABOR IS RIDICULOUS!

oldngivout

iTrader: (8)

Well, let's look at it this way. You could have bought the new MAF & IACV and installed them yourself.
You could have then sourced a good used ECU, as many others on this board have done. Install it yourself, then have the car towed to the dealer so that they could program the immobilizer system.

Prices for used parts may vary, but in the end you would have spent a similar amount of money, plus you get a warranty on the work. Not really that bad a deal, if that level of repair is intimidating.

300ZX TT

i agree...i did think of going that route...new parts would have cost me about $850 or so...but i just wasn't comfortable messing with too much electrical stuff...i've swapped eproms and done just about everything else on my Z, but i'm so familiar with that car...i didnt want to risk anything here, and plus the maxima is my DD so i needed the car back ASAP, so it works out that i got a rental for free also

reyrey

If you have not done the ECM and IACV replace, I'd talk yo Dave B. first about gettting the parts. I live in Toronto (Canada) area and bought my parts from Dave B. Dave also told me to disconnect the engine mounts., if your car is equipped with one. These electrical motor mounts conrol the vibration of the engine, I believe. Dave said these are also known to short out the ECM if they go bad. I did and engine idles fine. From time to time engne throw a knock sensor code. I believe this may be related to the electrical motor mounts being disconnected.

By the way, what happened with my max when the IACV killed the ECM, my idling shot up and we could not bring ths down and the car stalled as you described.

P. Samson

This unfortunately is just Gen. 5 history repeating itself. Dumbass IACV design compared to the Gen. 4. If you have an idle issue (particularly if accompanied by the P0505 code) with a Gen. 5 do not ignore it in case it is actually caused by a failing/failed IACV. If the IACV stepper motor/pintle seizes and the ECM is attempting to move it for "some extended time" in it's attempt to control the idle to the programmed limit, there is a transistor or a transistor array in the IACV circuit on a circuit board in the ECM that can/does "fry". There does not appear to be any circuit load limiter used and the fuses don't appear to protect the circuit other than a dead short I guess. There are photos somewhere on this website/forum of this damage. Coolant contamination of the IACV stepper motor appears to be a prime cause of IACV seizure, so if you notice coolant leaking from the TB, deal with it ASAP. A quick check to see if the IACV stepper motor is basically "operating" is to listen for it when you turn the IGN. sw. from OFF to ON (open the hood and listen for a kind of "buzz" or "frog sound" that lasts for about a half second). You can also remove the stepper motor and pintle only (not the whole assembly) by removing the two motor attach bolts with the TB insitu. That will also allow you to inspect inside the housing for coolant/crud etc. and allow you to visually check for operation as above. The auto's ECM controlled mounts as mentioned above have also been suspected in ECM failures, and there was a SB associated with SOME of these mounts in early production Gen. 5 cars, but whether that really prevented subsequent failures, I kind of doubt it. If you hear a continuous "buzzing" in the engine compartment after turning off the ignition switch, that is a sure sign that you've got an issue with the electronic mounts or the ECM, or that circuit. Disconnect the neg. battery cable until you can disconnect each mount harness connector. If you need an ECM I believe that there are still companies that repair/exhange our ECMs at a better price than the dealers. I haven't checked this in about four years, so you do the search. Maybe nobody can beat Dave B's price now.

98 MAX

I had the same problem with my 98 all it was was a vaccume seal leak right on the top of the engine it was dyin on me when the rpms went below 1000 that should be your problem

s14.3

I have the P0505 code on my 2000 5 speed Maxima. I changed the IACV to a new one (supposedly, bought from another member on this board), and check engine light still on. I removed the ECM to take a look inside, but i could not see any damage to the chip inside the ECM. I installed the ECM back on car, and the check engine light was not on for 2 days, then it came back. The car idle around 800 to 900 rpm when warm, occasionally drop to around 750. My questions are:
1. When i turn on the key, i do hear the buzz noise coming from IACV, i am assuming that the IACV is good then, right? NO coolant leak that i can see at all.

2. With new IACV and check engine light still on, is it possible that ECM still fried, even no visual damage can be seen? The car does not idle like the rest of the cases, that it does not idle at 1700 rpm, just around 800 rpm. Is it possible that i only need the IACV relearn then the check engine light will be gone? Or do i have to go ahead and replace the ECM and reprogram for the key and has the dealer do the IACV relearn at that point? THe dealer here are extremely expensive, they want 200 to 300 just to replace ECM (i supply the ECM) and reprogram it.

Anyone has similar experience or know something about it? Any help will be apppreciated, i just hate to waste money to replace the ECM if it is good. Thanks.

copilot1991

I had a problem with my car dieing, threw up a code for the EGR. Turns out it was just missing a ground. That fixed the light, but following what I read in the site I checked my MAF by cleaning and the bogging and dieing stopped. As soon as I was ready to leave the AutoStore lot, it threw the light again. He tried to play it off as the MAF but it looked fine and we just cleaned so I told him, "I just got this back from the mechanic with no lights, cleaned the MAF sensor to stop the power loss, and now I have a light... I want you to check it."

When he did, he turned up a P5050 code and that's the IACV, now it has clues on what could be causing it but I dont know what to do:

1). Large Vacumn leak
2). blocked intake manifold or exhaust
3).thottle body damage
4). engine mechanical condition

I just got it back from the mechanic and it wasn't throwing any lights before, now after cleaning the MAF it has more power and now it throws up the light, WTF?

513Chillz

Would somebody please tell me how to remove the screws from the ecu harness in order to remove the ecu.. theres not enough space to unscrew them.. ive removed the two covers on the sides of the ecu still no luck... I have new ecu but cannot remove old PLEASE ADVISE

shamguard

What does the term MAF and IACV mean, I have a P0100 CODE ony my car a 97 Maxima GLE,

BronxSleeperMax187

[quote=shamguard;7574978]What does the term MAF and IACV mean, I have a P0100 CODE ony my car a 97 Maxima GLE,[/quote
Mass air flow Senser or Make A Freaking.... effort to search it


Iacv is in the first post up top

browndo04

i am new to this forum,so i have to reply to 15 new threads. so i have a 2001 Nissan Maxima and i just had the IAC replaced on it. I took to dealership to have reprogrammed,and they came back and said ecm was fried and the thing that fried it was the Electronic engine mount. Total cost for parts and labor 1,800.. trying to rip me off. So i found a company that will rebuild ecm and he told me that the EEM does not have to be connected? is this true? Also i was going to take off ECM but not sure how, sure i can figure out. Also if you take off Ecm and send to be repaired, when you get back does it have to be reprogrammed again at a stealership?? its for a 2001 nissan maxima. Thanks for the help.

Ghost_54

iTrader: (13)

First off welcome to the site, and hopefully to save you from getting flamed please look at the dates on the original threads so as to not bump something that is very old ... There is a thread titled " I am new here but have a question" always a good place to start.

It is not uncommon for the IACV to fry the ECU as well as the electronic motor mount can do the same thing which is why you will see a number of threads that say to unplug the motor mounts to prevent the ECU from being fried, it is fine to leave them unplugged you may feel a little bit more of a vibration when the car is at idle and no vibration when in motion. I do believe even after you have had the repair done to the ECU as well as resolved your issue with the IACV you will need a reprogram done. The dealer will also have to do an idle relearn for the new IACV

browndo04

Does anyone know how to disconnect electronic engine mounts on 2001 nissan maxima?