IAC relearn

Tiny
SZALKUSKT
  • MEMBER
  • 2000 NISSAN MAXIMA
  • 3.0L
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 140,000 MILES
Hi, I did a valve cover change and also cleaned the upper intake plenum and throttle body and IAC valve. I took apart the intake plenum and disassembled the vias components enough so I could clean the plastic intake plenum. I thoroughly cleaned the plenum and after it was very clean I put it all back together and also the EGR valve. After putting everything back together the car would not idle on start up and I had to use the accelerator to keep rpm high to run. Basically car would not idle and there are no codes. Being that I did not remove the IAC from the throttle body while cleaning and only soaked the bypass cavity with throttle body cleaner and after some reading on the internet I bought a new IAC valve and also took the ECM out and took the cover off and inspected the circuit board for melted or burned areas and it looked fine. I changed the IAC valve and put it back together and ran the car and car will not idle and once warm will hold various rpms after moving the throttle. I want to try a IAC reset or relearn procedure but have not found a good how to video or stepson internet specific for my car. There are none or never were codes. Car ran fine before I took everything apart and changed valve cover gaskets and disassemble all these components. I think since I meticulously put everything back together properly I might have hurt the original IAC valve with so much throttle body cleaner and so I elected to change it. I am looking for the IAC relearn steps I can do at home without a tester.
Tuesday, January 3rd, 2017 AT 7:31 PM

7 Replies

Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Drive it over forty mph for a short distance and IAC should reset. if continues scan for codes and check fuel pressure and for vacuum leak. See link.
https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator
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Wednesday, January 4th, 2017 AT 12:24 PM
Tiny
SZALKUSKT
  • MEMBER
  • 274 POSTS
Right now I am unable to drive because car is not registered and I am afraid If I get stuck somewhere wont be able to drive home. Is it possible to do this if I jack up wheels off the ground and keep speedometer over 40 mph for a bit and it will reset in theory? Also, Is it possible to use the ignition key off on cycles and accelerator pedal depression combinations to reset it as I have seen it done with some of these nissan models on you tube?
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Thursday, January 5th, 2017 AT 7:18 PM
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
I cannot advise you to do that. It has to be driven though to reset it. You can try the Nissan thing but may not help
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Friday, January 6th, 2017 AT 6:18 AM
Tiny
SZALKUSKT
  • MEMBER
  • 274 POSTS
I ran it up to operatind temperature and engine seems to be idling good now. I also did the nissan IAC relearn procedure where you pull the brown connectore on the tps and reinstall it within 5 seconds. Car seems to be ok enough to drive it later.
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Sunday, January 8th, 2017 AT 10:39 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,643 POSTS
Hey SZALKUSKT

Please let us know what you find so it will help others.

Best, Ken
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Thursday, January 12th, 2017 AT 10:16 AM
Tiny
SZALKUSKT
  • MEMBER
  • 274 POSTS
Currently the iac relearn procedure that nissan described to do seems to be working. Car runs good. Im gonna start ir up and run it tomorrow some more. I also towed it to a place where I could drive it over 40 mph also for a short distance.
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Friday, January 13th, 2017 AT 10:28 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,643 POSTS
Good to hear, keep us posted.

Best, Ken
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Saturday, January 14th, 2017 AT 9:33 PM

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