Replaced IACV, luckily ECM is fine.
 

Hello everyone, I'm an owner of 2000 maxima with 130k. The IACV went out 2 months ago. Through reading I unplugged the 2 connectors to the electronic motor mounts. I continued to drive the car through the winter. The car started up everytime and did not stall.

When the weather got warmer. I opened up the ECM module and thank god, no traces of burnt were found, sight or smell. I put the ECM back in and continued driving for 1 week. As yesterday, I finally replaced the IACV (Hitachi brand). The process to remove and replace was fairly easy. I did find some traces of gunk and coolant in my intake manifold. When everything was back together, I unplugged the battery for 20min. Started the car up and it was normal again. I did not have to perform an idle relearn.

I just want to thank everyone who provided information to this problem. This issue was such headache. Hopefully my share of information will help someone in the future.

Mr. Hybrid,

Welcome aboard, and thanks for letting us know how your project went. I'm getting ready to do mine as preventative work.

Where did you buy your IACV and how much was it? I'm going to guess we don't want to go cheap on this one and OEM is the only way to go?

I ordered mine from Rockauto.com cost around $140. Hitachi is a Japanese company and I know they make also OEM batteries for Toyota. $300 for an OEM IACV seems pricey to me. Sometime in the future I plan to do the coolant bypass modification as a more safer route.

This has brought up a question. I'm sure Nissan is aware of this issue. But what have they done to help the customer prevent this problem? Does Nissan sell a updated version of the ECM?...or they let the problem to be on going everytime the IACV fails, ECM burns.

I have a feeling that the R&D department has been working on more pressing issues than cars sold 16 years ago. Their solution for toasted ECM's is very likely, "Can I interest you in a 2016 Altima, or a Maxima perhaps?"

Believe me... it doesn't make me happy either. but it's business. These cars are long sold and "done" to Nissan.

Daughter's Max had 2 IACV go and neither damaged the ecu.
Why go with the OEM that certainly goes bad as can be viewed by
posts on the Forum?
First one I replaced was an used unit from an Infinity with 32,000 miles,
then when that one went south, I purchased a new aftermarket unit and
it's still on the car.
Save your money and look over on ebay/Amazon.

That's a valid point, Turbo.

Did the IACV come with a gasket and the screws? Thanks!

I found gunk in my throttle body. Some times over time with hot/cold cycles the throttle body warps and the coolant leaks past the rubber IAC gasket. My dad I machine the T body flat again with set of good high end metal files, there were quite a few high and low spots which eventually we worked flat with very steady hands. This way it's not prone to leak again any time soon with good flat and smooth surface for the gasket ans sealant to adhere to and seal against.

Also we used a sealant on the gasket as well, silicone. it was allow to cure for a little bit so it would be little bit stiff/hardened before screwing/bolting IAC to the TB. Then once it was it was allowed to cure more, don't want silicone in the coolant or intake, nor break that seal before properly cured.

If you do use sealant DO NOT apply it directly at least no generously, just thin coating on the gasket and if apply directly apply it the channel/grove the gasket goes in, also very light/think coat, it doesn't take much and too much can prevent good seal or the spill over and can wind up in the engine.

A bit of attention to detail can go a long way.

EDIT: IAC should come with a gasket and screws. I ordered OEM (Hitachi) on eBay.

from what i had read on the forums oem lasted much longer and was less likely to go bad after just 1 month. maybe i missed the posts you were reading

No one mentioned one month, at least I didn't, but the point I was making was that as the OEM was prone to failure, why spend $321 for an OEM part (1 year warranty), when and aftermarket IACV can be had for as little as $30 and comes with a Lifetime warranty. Buy 2 and if one fails, install the other and send the defective unit back under warranty. The aftermarket on the daughter's Max has been on there for maybe 100,000 miles, no problems.
Just an example:
http://www.ebay.com/itm/IACV-Idle-Ai...dVKJEv&vxp=mtr

The above from China, but there are others available US origination, but possibly imported from Asia.

I got one from orailys it was a borg warner.

Stock one got fried it looks like the stock o ring got a leak and the coolant when in there.

This is just another reason why you do the coolant bypass. There's absolutely no reason for coolant to be in a TB, period (just like 99.9% of fuel injected motors don't need anti-vapor lock systems, but they installed them on some anyway).

My IACV went out on my 2001 GLE back in 2011. I took it to a garage and they mentioned they had to re-learn the ECU but don't have the technology and want me to have it towed to Nissan. When I got to Nissan they mentioned the engine mount shorted out the ECU and they need to replace the ECU.
$918.58+75overnight delivery. with the IACV which was $390.73 and ECU $1384. $300 labor to Nissan So it was $1796.96 all together. + the 300 for the bill at the previous garage. Where they didn't even have the technology to re learn the ECU. so it was more like over $2000
A while later in 2015 I broke down and got a tow back home. I figured out ultimately it was a starter and replaced it.
While replacing the starter I saw the engine mount wire they cut.

The two engine mounts underneath? SO you unplug those and the car acts fine?

some say to rev a little before disconnecting so they stay in hard mode. replacing with manual ones work too

I don't get it. If your IACV motor went out on you, then how could you just unplug two engine mounts and drive all winter? What code did they get when you took it in? How did you know it was an IACV motor?

iacv and mounts are 2 separate things, both which can harm your ecu.

if you disconnect your mounts the car should drive fine

if your iacv is toast you will have to get a new one

I understand you don't need your engine mounts connected but How would you drive all winter on a bad IACV? Did you just drive anyway and ignore the engine code stored for a bad IACV?

So are the new Maxima Engine mount circuits assigned fuse?

maximatech 12: Read this- https://drive.google.com/file/d/0B6O...psNVBqUVk/view - it will clear up a lot of things you are confused about.

Is this a TSB or something?

Great read, thanks for posting.

I wish I would've read up on the TSB "The Buzz" back in 2010 when I bought the car. I'm one of the max owners that had this issue so this really helps.
I had a lot of questions while walking out of the garage after the repair but I just trusted the techs and paid up. Right now I would like to avoid this from happening again.
I've had other members claim it was a scam and the dealership lied to me however I knew they were accurate in their findings.
A lot of times there is a lot of confusion when there is so much damaged. I usually trust the techs and then later try to research it.

I have an issue with you posting this garbage and publishing it to good car owners that care about their vehicles and pay a lot of money to drive.
Your ruining the reputation of the org.
The coolant is in the throttle for a reason and if you can't come back with a post that justifies the coolant in the throttle then you shouldn't advise other Max owners to bypass it. :mad::mad::mad::mad:

To all the other Max owners:

DONT LISTEN TO ANY BULLETIN UNLESS IT HAS A GENUINE NISSAN LOGO ON IT!!!!

:Police::rofl:

Perhaps it was the throttle body bypass that made your battery split:chuckle:

Good point thanks for the heads up.

I got a new battery going in this weekend and am going to carefully hook the throttle chamber back up.

To all the other Max owners:
maxiiiboy's article summarizes a lot of information from previous threads here. you can do your own research and reach the same conclusions. maximatech12 has been here a month and refuses to search for himself or listen to anyone's advice. it's easy to draw your own conclusions about which source is credible

I can verify this for anyone who comes across this in the future. maxiiiboy is a well respected and long time member here. maximatech12 has proven to be either a high functioning troll or a very low functioning individual. He's proven this through several posts as well as PMs.

If anyone needs a ecm let me know.

Its garbage don't read it just trash it!!!

Ok so I tested the iac itself and I have no resistance, also it does not move at all when I turn the key on and off. So I def need a new one, and I'm going to pull the ECM to see if it's burnt.

Now, if the ECM is not fried, if I put in new iac and switch fuse #58 to 7.5 amp will that protect the ecm from frying?

I did disconnect the motor mount wiring and I'm gonna grab some fresh hose to do the coolant bypass while I'm at it.

If the ecm is fried, am I able to buy the replacement chip and swap it myself? I know how to solder so I think I can handle it. Can't seem to find the chip by itself online.

No, unfortunately the 7.5A fuse will NOT protect the STA509A transistor driver in the ECU. That transistor can only withstand 3A current (6A in pulse mode).

You can try. You can also try a TV repair shop.

Also, make sure you have a good set of screwdrivers before taking it apart. The housing is held with very tight screws made of soft metal. The wrong screwdriver will strip them quickly.