Throttle body and very high rpms

Johnathan Logan · March 22, 2020

Today I got a code for the throttle body sensor or what not. After looking online people said cleaning it out would help. There was no engine problems at this point everything was running smooth it was just the check engine light I wanted to get rid of. After taking it apart and cleaning it i cranked it and it goes up to 3k rpms and scared me I looked online and people said oh it has to relearn itself crank for 3 min and shut off for a min repeat well it stayed between 2500 and 3k rpms the whole time never going back down. So I just gave in went and bought a whole new throttle body with new sensor on it. After I installed it i cranked it up and it went to q500 rpms and then leveled back down to 500 or 600 like it usually was. So i thought I had fixed it so i shut it off and when i cranked it back up it was back at 3k rpms again doing the same thing. Does anyone know what may be the problem. Crazy it worked right the first crank after replacement but since then its back to running high rpms.

tlaw91 · March 22, 2020

What are you working on

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Johnathan Logan · March 22, 2020

It's a 2009 gmc sierra 1500 5.3l 4x4

CamGTP · March 22, 2020

Did you clear the codes prior to doing the 3min idle, 60 seconds off, 3min idle relearn?

If that doesn't work, you may need a scan tool that can enable the relearn.

Johnathan Logan · March 22, 2020

Yea I unhooked the battery for awhile before cranking it but it's weird it worked perfect when i cranked it the first time after replacing it but after i shut it off and went to crank it back up it went back to the revving really high

tlaw91 · March 22, 2020

You need to relearn the idle with a scan tool. Isn’t working on cars fun? [emoji849]

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Michael McBee · March 22, 2020

I don't have a Sierra, my vehicle is a 2012 Canyon. The Canyon has what is called ECT, Electronically Controlled Throttle. Basically the gas pedal has a position sensor that command the throttle body to open/shut based on pedal position. You replaced the Throttle Body, cleared the codes, and relearned the component. If Sierra is also ECT take a look at the pedal or ECM. It is either software or hardware at this point. At least you know the throttle body is good

Johnathan Logan · March 22, 2020

13 hours ago, Johnathan Logan said:

Today I got a code for the throttle body sensor or what not. After looking online people said cleaning it out would help. There was no engine problems at this point everything was running smooth it was just the check engine light I wanted to get rid of. After taking it apart and cleaning it i cranked it and it goes up to 3k rpms and scared me I looked online and people said oh it has to relearn itself crank for 3 min and shut off for a min repeat well it stayed between 2500 and 3k rpms the whole time never going back down. So I just gave in went and bought a whole new throttle body with new sensor on it. After I installed it i cranked it up and it went to q500 rpms and then leveled back down to 500 or 600 like it usually was. So i thought I had fixed it so i shut it off and when i cranked it back up it was back at 3k rpms again doing the same thing. Does anyone know what may be the problem. Crazy it worked right the first crank after replacement but since then its back to running high rpms.

Update....i changed gaskets this morning thinking that would help well when i cranked it up it actually helped it was running around 1k and 700 rpms so normal looking. But as soon as you touch the gas even slightly it shoots to 3k rpms and stays around there. So idk at this point lol