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Throttle Bottle Idle Air Re-learn

158K views 112 replies 72 participants last post by  westslope 
#1 · (Edited by Moderator)
I would like to clean out the thottle body (using Throttle Body Spray Cleaner),

but I have stumbled upon some forums that say something about a rough idle, and that the computer has to "relearn" the idle/throttle position?

Something about a "Idle Air Volumn Relearn" procedure?

I didnt seen anything in the Factory Service Manual about this.

Saw somewhere about having to drive x amount of time at a certain speed (while patting your head and rubbing your tummy) to allow the computer to relearn.

This sounds like a real hassle.

here is a post on the Frontier forum;
http://www.clubfrontier.org/forums/f8/i-need-help-high-idle-problem-36101/

This nimrod used break cleaner, but aside from that, what concerns me is this "relearn procedure"

Anybody have any experience with this, and cleaning the thottle body?

I read USMC_Xterra's post about cleaning the throttle body, but he didnt say anything about a "relearning procedure".

http://www.thenewx.org/forum/showthread.php?t=3143&highlight=throttle+body

Thanks !

~Lewis
 
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#2 ·
You'll find the procedure on page EC-91 in the "Engine Control" section of the 2005 service manual. It's not too hard, but timing is critical. It took me three times before I mastered it. It's a bit like Dance Dance Revolution. ;)
 
#5 · (Edited)
I remembe way back they had somethin like that for nintendo 64 and we would get drunk and play golden eye but at the end of the night we were playin that stupid dance game it would turn into a competition. Man goldeneye was the best first person shooter of its time.
Posted via Mobile Device
 
#6 ·
i am not sure if you planned on removing the throtle intake body, i would suggest it. remember that you will have to disconect the 2 small hoses for the coolant lines and put something to cap them while you clean the throtle intake. i was not happy to see a plastic screen that did not allow access to the the intake housing area....we simply sprayed into it to try to loosen the nasty black stuff. so if you dont mind the time to take off the intake housing i would suggest you do.... this way you will have access to the whole system and be able to clean it perfect. good luck
 
#8 ·
i am not sure if you planned on removing the throtle intake body, i would suggest it. remember that you will have to disconect the 2 small hoses for the coolant lines and put something to cap them while you clean the throtle intake. i was not happy to see a plastic screen that did not allow access to the the intake housing area....we simply sprayed into it to try to loosen the nasty black stuff. so if you dont mind the time to take off the intake housing i would suggest you do.... this way you will have access to the whole system and be able to clean it perfect. good luck

that black plastic screen can be pulled out. just be careful cause there is a small clip that holds it in. i pulled the screen and cutoff the grid part, sanded down the edges and put the outer rim back into the intake.
 
#14 ·
That's funny, I never really bothered to look at the TB long enough to notice the coolant lines. I used to have a '96 Camaro and did that to my LT1. That was the big free/cheap mod in the 4th gen Camaro world. It was determined that at regular operating temperature the heat of the coolant did affect the air coming into the throttle body. Somebody actually dyno'd it and saw a 5-6 RWHP gain.
 
#9 ·
It simply amazes me how many people throw curveballs on the internet.


My experience is that if it is really dirty, disconnect the battery while you are doing the procedure: unhook the ground cable.

I've ported Nissan throttle bodies (bell-mouthed) up to the point of where the blade touches down and have had no problems with any of the cars idling as long as I had disconnected the battery.

The only time I had a problem was when I did not disconnect the battery, cleaned a nasty unit of which the computer had compensated for, and then I proceded to run the car without disconnecting the battery. After a week it finally relearned. I just had to see if it would do it on my personal car.

3M makes a good T-bod cleaner.

I opened all t-bods by hand and none of the dozen DBW's (drive by wire) units broke. Treat it with respect.
 
#10 ·
Here is the manual idle relearn procedure I found.

Idle Air Volume Learning

DESCRIPTION
Idle Air Volume Learning is an operation to learn the idle air volume that keeps each engine within the specific
range.

It must be performed under any of the following conditions:
 Each time electric throttle control actuator or ECM is replaced.
 Idle speed or ignition timing is out of specification.

PREPARATION
Before performing Idle Air Volume Learning, make sure that all of the following conditions are satisfied.
Learning will be cancelled if any of the following conditions are missed for even a moment.

 Battery voltage: More than 12.9V (At idle)
 Engine coolant temperature: 70 - 100°C (158 - 212°F)
 PNP switch: ON
 Electric load switch: OFF
(Air conditioner, headlamp, rear window defogger)
On vehicles equipped with daytime light systems, if the parking brake is applied before the engine
is started the headlamp will not be illuminated.
 Steering wheel: Neutral (Straight-ahead position)
 Vehicle speed: Stopped
 Transmission: Warmed-up
For A/T models with CONSULT-II, drive vehicle until “ATF TEMP SE 1” in “DATA MONITOR” mode of “A/
T” system indicates less than 0.9V.
For A/T models without CONSULT-II, and M/T models, drive vehicle for 10 minutes.

Without CONSULT-II

NOTE:
 It is better to count the time accurately with a clock.
 It is impossible to switch the diagnostic mode when an accelerator pedal position sensor circuit
has a malfunction.
1. Perform EC-89, "Accelerator Pedal Released Position Learning" .
2. Perform EC-89, "Throttle Valve Closed Position Learning" .
3. Start engine and warm it up to normal operating temperature.
4. Check that all items listed under the topic PREPARATION (previously mentioned) are in good order.
5. Turn ignition switch OFF and wait at least 10 seconds.
6. Confirm that accelerator pedal is fully released, then turn ignition switch ON and wait 3 seconds.
7. Repeat the following procedure quickly five times within 5 seconds.
a. Fully depress the accelerator pedal.
b. Fully release the accelerator pedal.
8. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 20 seconds until the MIL stops
blinking and turned ON.
9. Fully release the accelerator pedal within 3 seconds after the MIL turned ON.
10. Start engine and let it idle.
11. Wait 20 seconds.
12. Rev up the engine two or three times and make sure that idle speed and ignition timing are within the
specifications.
 
#18 · (Edited)
Here is the manual idle relearn procedure I found.

Idle Air Volume Learning

DESCRIPTION
Idle Air Volume Learning is an operation to learn the idle air volume that keeps each engine within the specific
range.

It must be performed under any of the following conditions:
Each time electric throttle control actuator or ECM is replaced.
Idle speed or ignition timing is out of specification.

PREPARATION
Before performing Idle Air Volume Learning, make sure that all of the following conditions are satisfied.
Learning will be cancelled if any of the following conditions are missed for even a moment.

Battery voltage: More than 12.9V (At idle)
Engine coolant temperature: 70 - 100°C (158 - 212°F)
PNP switch: ON
Electric load switch: OFF
(Air conditioner, headlamp, rear window defogger)
On vehicles equipped with daytime light systems, if the parking brake is applied before the engine
is started the headlamp will not be illuminated.
Steering wheel: Neutral (Straight-ahead position)
Vehicle speed: Stopped
Transmission: Warmed-up
For A/T models with CONSULT-II, drive vehicle until “ATF TEMP SE 1” in “DATA MONITOR” mode of “A/
T” system indicates less than 0.9V.
For A/T models without CONSULT-II, and M/T models, drive vehicle for 10 minutes.

Without CONSULT-II
NOTE:
It is better to count the time accurately with a clock.
It is impossible to switch the diagnostic mode when an accelerator pedal position sensor circuit
has a malfunction.
1. Perform EC-89, "Accelerator Pedal Released Position Learning" .
2. Perform EC-89, "Throttle Valve Closed Position Learning" .
3. Start engine and warm it up to normal operating temperature.
4. Check that all items listed under the topic PREPARATION (previously mentioned) are in good order.
5. Turn ignition switch OFF and wait at least 10 seconds.
6. Confirm that accelerator pedal is fully released, then turn ignition switch ON and wait 3 seconds.
7. Repeat the following procedure quickly five times within 5 seconds.
a. Fully depress the accelerator pedal.
b. Fully release the accelerator pedal.
8. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 20 seconds until the MIL stops
blinking and turned ON.
9. Fully release the accelerator pedal within 3 seconds after the MIL turned ON.
10. Start engine and let it idle.
11. Wait 20 seconds.
12. Rev up the engine two or three times and make sure that idle speed and ignition timing are within the
specifications.
Don't forget these! Here are steps 1 and 2 of the idle air volume learning procedure.

Accelerator Pedal Released Position Learning

DESCRIPTION
Accelerator Pedal Released Position Learning is an operation to learn the fully released position of the accelerator pedal by monitoring the accelerator pedal position sensor output signal. It must be performed each time harness connector of the accelerator pedal position sensor or ECM is disconnected.

OPERATION PROCEDURE
1. Check that accelerator pedal is fully released.
2. Turn ignition switch ON and wait at least 2 seconds.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Turn ignition switch ON and wait at least 2 seconds.
5. Turn ignition switch OFF and wait at least 10 seconds.

Throttle Valve Closed Position Learning

DESCRIPTION
Throttle Valve Closed Position Learning is an operation to learn the fully closed position of the throttle valve by monitoring the throttle position sensor output signal. It must be performed each time the harness connector of electric throttle control actuator or ECM is disconnected.

OPERATION PROCEDURE
1. Check that accelerator pedal is fully released.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
Check that throttle valve moves during above 10 seconds by confirming the operating sound.
Special Thanks to SeXterraPA and Shiny for the instructions on the Idle Air Volume Learning procedure. It worked perfectly (on the third try).

Lately, my X has been idling at approximately 1,100 RPM. So, today I cleaned my throttle body and my MAF sensor in the hope that my idle would adjust. Afterward, the X seemed to breath much better, but the idle was still really high.

I tried Muzikman's suggestion of disconnecting the battery, but that didn't work for me. It took me 3 attempts of doing the manual re-learn, but it finally worked. Now my idle is at approximately 650 RPM. I'm really curious to see what will happen to my MPG. Hopefully, I'll regain some "lost" MPG.

EDIT: SeXterraPA and Shiny's instructions should be a sticky in the How-To section. I didn't see it there, so if it is forgive me.
 
#11 ·
Don't forget these! Here are steps 1 and 2 of the idle air volume learning procedure.

Accelerator Pedal Released Position Learning

DESCRIPTION
Accelerator Pedal Released Position Learning is an operation to learn the fully released position of the accelerator pedal by monitoring the accelerator pedal position sensor output signal. It must be performed each time harness connector of the accelerator pedal position sensor or ECM is disconnected.

OPERATION PROCEDURE
1. Check that accelerator pedal is fully released.
2. Turn ignition switch ON and wait at least 2 seconds.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Turn ignition switch ON and wait at least 2 seconds.
5. Turn ignition switch OFF and wait at least 10 seconds.

Throttle Valve Closed Position Learning

DESCRIPTION
Throttle Valve Closed Position Learning is an operation to learn the fully closed position of the throttle valve by monitoring the throttle position sensor output signal. It must be performed each time the harness connector of electric throttle control actuator or ECM is disconnected.

OPERATION PROCEDURE
1. Check that accelerator pedal is fully released.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
Check that throttle valve moves during above 10 seconds by confirming the operating sound.
 
#75 ·
Here is the manual idle relearn procedure I found.

Idle Air Volume Learning

DESCRIPTION
Idle Air Volume Learning is an operation to learn the idle air volume that keeps each engine within the specific
range.

It must be performed under any of the following conditions:
 Each time electric throttle control actuator or ECM is replaced.
 Idle speed or ignition timing is out of specification.

PREPARATION
Before performing Idle Air Volume Learning, make sure that all of the following conditions are satisfied.
Learning will be cancelled if any of the following conditions are missed for even a moment.

 Battery voltage: More than 12.9V (At idle)
 Engine coolant temperature: 70 - 100°C (158 - 212°F)
 PNP switch: ON
 Electric load switch: OFF
(Air conditioner, headlamp, rear window defogger)
On vehicles equipped with daytime light systems, if the parking brake is applied before the engine
is started the headlamp will not be illuminated.
 Steering wheel: Neutral (Straight-ahead position)
 Vehicle speed: Stopped
 Transmission: Warmed-up
For A/T models with CONSULT-II, drive vehicle until “ATF TEMP SE 1” in “DATA MONITOR” mode of “A/
T” system indicates less than 0.9V.
For A/T models without CONSULT-II, and M/T models, drive vehicle for 10 minutes.

Without CONSULT-II

NOTE:
 It is better to count the time accurately with a clock.
 It is impossible to switch the diagnostic mode when an accelerator pedal position sensor circuit
has a malfunction.
1. Perform EC-89, "Accelerator Pedal Released Position Learning" .
2. Perform EC-89, "Throttle Valve Closed Position Learning" .
3. Start engine and warm it up to normal operating temperature.
4. Check that all items listed under the topic PREPARATION (previously mentioned) are in good order.
5. Turn ignition switch OFF and wait at least 10 seconds.
6. Confirm that accelerator pedal is fully released, then turn ignition switch ON and wait 3 seconds.
7. Repeat the following procedure quickly five times within 5 seconds.
a. Fully depress the accelerator pedal.
b. Fully release the accelerator pedal.
8. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 20 seconds until the MIL stops
blinking and turned ON.
9. Fully release the accelerator pedal within 3 seconds after the MIL turned ON.
10. Start engine and let it idle.
11. Wait 20 seconds.
12. Rev up the engine two or three times and make sure that idle speed and ignition timing are within the
specifications.
Just found this thread while searching, just want to make sure I do this right, do i actually need to disconnect the battery at all even if im not cleaning the TB? And its seems you NEED to do the process three times in a row correctly for it to work right?
 
#12 ·
I did not have success doing this, because I found the manual how-to (without Console-II) while I was sitting in the sitting Nissan dealership waiting area. I asked them for my keys and gave it a whirl, but I no success before they needed to pull it into the service bay. D'oh!
 
#17 ·
for my 2 cents, I got it to work by doing Accelerator Pedal Released Position Learning before doing the "Throttle Valve Closed Position Learning" every time I had to go thru the throttle valve closed position learning... so if I didn't get it right, I had to go back to square one so to speak and do the ACPRL first...

maybe it was implied, but I found this is what got it for me and I am not that smart to have to infer...

and it sounds like you should do this regardless of whether you take the neg off the battery before you clean it (I did and did ECU relearn after and still had 1000+ idle) I also got a code -0507 or 0570 after my ECU relearn ride - it said idle control... cleared it, and did this, back to 625... no more code...

mine was pretty filthy so I am sure it had a long way to go to compensate for being clean... lesson for me is to do it every 10k or so(any advice?)... I have a K&N for the past 15k so that is probably why...
 
#20 ·
well i did this last night ... i cleaned my throttle plate form all the goo and and black crap. it started running rough after that .. actually i used to be able to spin the back tires in a parking lot .. and i could no where near do any of that felt like its nose was stopped up ... i did the relearn and it will throw you back in your seat when its good and clean ..
 
#22 ·
Anyone can tell where and what is the PNP switch?

I am gong to do the:
-Accelerator Pedal Released Position Learning
-Throttle Valve Closed Position Learning AND
-Idle Air Volume Learning today.
That is the perfect order to do the steps in.

I don't know what the PNP switch is, but I made sure that I didn't have any accesories on (radio, lights, A/c, etc.). It wasn't too fun because I did it while it was dark out, so I had to use a flashlight while reading the instructions and performing all the steps. Also, I didn't have a watch / stopwatch with me, so I had to count "one-one-thousand, two-one-thousand..." It took me 3 tries to get it right, but it did work. The vehicle will seem like it is about to stall when it kicks the idle down to 650 RPM, but then it will level off there.

Good luck, and don't get too worried if it doesn't work on the first try.
 
#26 ·
I dealt with this on my '03 Maxima, also DBW. First, it helps to use a stopwatch, because the timing is critical.

The problem I had was every time I went through the steps, it worked great, idle would go right to 650ish, until I restarted the car. It would go right back to 1000 with a high idle code.

What worked for me, and it took me a couple weeks to figure this out, was to do the relearn procedure successfully, shut the car off, then immediately do the whole procedure a second time. Then it worked perfectly. Good Luck!
 
#27 ·
So this afternoon I cleaned the MAF and throttle body, reconnected the battery and attempted to execute the relearning procedure. I (think) I've done it correctly, as the MIL blinks, becomes solid, and I release the accelerator. I then start the X and the idle is still around 850 RPM. Thoughts?
 
#41 ·
ditto, my gas mileage has been terrible, worse than normal w/ crappy winter gas.
 
#32 ·
A few more questions...

Hi all, great forum!

I cleaned my TB and MAF. Now my engine is idling at 950rpm and it's throwing a "High Idle" code at me. I've tried the relearn procedure a dozen times, and I'm about to try it a dozen more, but hopefully you can help me out and answer a few questions before I attempt this again:

I've been driving around with the high idle error code, should I clear the code before attempting the relearn procedure?

Should I disconnect and then reconnect the battery before trying the procedure again?

When the procedure works how will I know? Does it bump the rpms to 650 immediately?

Between attempts should I do anything to reset the procedure before starting over (if it doesn't work)?

Thanks in advance!
 
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