I have done the ECU reset, the throttle and acceleration relearns, and the Idle Air Volume Learning. The car will learn them fine, and even run fine. However after I re-start the car, all of the learning procedures are gone, and it throws code P0507 and I am back to square 1 (high idle issues, CEL).

Is there anyway to make the Idle Air Volume Learning "stick" to the ECM? Everytime I start the car, I need to do the Idle Air Volume Learning to get it to run properly.

I cleaned my throttle body initially, which is causing all of this horror. The dealership has told me to replace the throttle body...I have a feeling they may be trying to scam me.

 

How did you clean it? Did you physically move the throttle plate?

Did you do it with the battery disconnected before unplugging or reconnecting to the TB harness?


BTW - there's a new TB for sale in the Marketplace....
https://my350z.com/forum/engine/364355-brand-new-nissan-throttle-body-and-tps-200-shipped.html

 

I did physically move the throttle plate when cleaning, and didn't disconnect the battery. Had I read the forums prior to cleaning, I would have disconnected the battery, or if I didn't, have someone press the accelerator to move the throttle electronically.

Anyhow, last night I took apart the MAF, cleaned it with CRC sensor cleaner, removed the stock 350z tube, and re-installed the G35c intake system, made sure the vacuum/emission line was tight, reset the ECU, did the throttle/accelerator/idle-air relearn, and now the car is back to normal, with perfect idle. Even after restarts, and even after leaving the car parked over night, it still remembers it now.

I am thinking that the emission tube may have been too stretched when trying to reach the Z tube inlet (I am using a Z tube on a G35c), and may have caused for a vacuum leak.

 

I'm posting this same response in a few threads for this problem in the hope that someone else will benefit from it.

My idle problem is fixed, and by that, i mean the problem where it does not remember the correct low idle after turning the car off.

I did a couple of things differently during my last reset, which i'll explain below, but here's the points i used.

1) Car fully up to running temperature (required)

2) Reset performed per the book, correctly takes new idle setting (as normal each time i do it)

Two things i did/did not do this time that seemed to make the difference:

1) I turned off the interior fan before starting the procedure.

2) I did not rev the car a few times after the new lower idle had taken (even though the procedure calls for it)



I have no idea which of those two made the difference. All i know is, that it's now remembering the new idle and it's super smooth.

I had loaded a new map on the car a week previously, and i had the door open and the fans on low with the engine off for a few mins before starting it, i do have LED interior bulbs.
However, it complained of battery voltage too low and would not let me flash until i had closed the door and turned the fans off.

This has never been a problem before when flashing and whilst i don't think it's a problem directly, i'm wondering if it showed up another problem that perhaps contributed towards the issue.

The battery isn't that old but it's possible it's not as well as i thought, I'm thinking the battery voltage during the reset procedure, which is done with the ignition on but engine off, was causing a problem with the learning portion.


Short version;

* I came home and turned off the engine, fans and kept door closed.
* I ran the procedure, acquiring the lower idle, but omitting the rev testing at the end.
* Turned off the engine and shut the car up for the night.
* Everything perfect once up to running temperature the next day.


Hope this helps someone out.

 

There is a long list of things that must be in place before it will actually retain the new reset. The thread directly above mine outlines that as well as the FSM.

Most people that the relearn never sticks is due to not meeting all the requirements in the FSM. I'm pretty sure any obd codes will also cause a problem with the relearn.

 

Yeah, as much as we all read the voltage requirements along with the others, we all kind of assume that as the idle drops to where we want it, that all went well.