P0121 - dirty throttle body?

[The_bald_eagle_machine]

Would you guys consider this "dirty" been having a p0320 and today, p0121 code. Both throttle body related. Today while cruising the p0121 code started flashing the CEL at me but when I parked the car and let it idle while I plugged in my code reader. It went away. Cleared the DTC and it didn't come back while idling. Decided to clean my maf(which looked good) and then pulled the throttle body to find this. I panic ordered a new gm throttle body from Rockauto, but now I am wondering if I am fine.

Second question... is there a relearn process for the TBS? I unplugged the battery for a few minutes before pulling any of the connectors.

[bsn]

I would cancel the Rock Auto order and just clean the existing TB.

[Joe.G]

That is dirty and should be cleaned for sure, I would clean it before replacing it, use a throttle body safe cleaner. When I swapped mine for a Bo White ported unit I don't believe I did a relearn. A dirty TB can throw codes.

[The_bald_eagle_machine]

Cleaned and reinstalled. I will take it for a ride today and go ahead and cancel my rockauto order. Hopefully this clears up my issues, it has been really frustrating.

[1JEWLDSSRS]

Originally Posted by Joe.G

That is dirty and should be cleaned for sure, I would clean it before replacing it, use a throttle body safe cleaner. When I swapped mine for a Bo White ported unit I don't believe I did a relearn. A dirty TB can throw codes.

This for sure. When I did mine, there wasn't any relearn needed. It drove just fine tor me.

[The_bald_eagle_machine]

Well... a little update. I cleaned up the throttle body, and the code came right back as soon as I drove it down the street. Research of the P0121 codes seems to point towards 9/10 times it's the actual throttle position sensor on the pedal... so on top of my throttle body that is in the mail, I have a new pedal coming as well. Both GM Genuine... $400 in total from Rockauto. Fingers crossed this is the end of my issues.

[Joe.G]

I'd swap the pedal and start there, maybe send new throttle body out for porting prior to install.

[CamaroDreams76]

Throttle position sensor on the pedal. I would have guessed the actual throttle position sensor in the TB. I've had to replace 3 now.

As for relearn, I never even unplugged the battery when I swap the electronic side. I haven't had to do a relearn yet. I also went back and forth between Bo's stage 2 and stage 3 TB.

[TheBrightSide]

Originally Posted by CamaroDreams76

Throttle position sensor on the pedal. I would have guessed the actual throttle position sensor in the TB. I've had to replace 3 now.

As for relearn, I never even unplugged the battery when I swap the electronic side. I haven't had to do a relearn yet. I also went back and forth between Bo's stage 2 and stage 3 TB.

What exactly does the throttle position sensor re-learn exactly entail..? And like you, I’ve taken off my stock throttle body, swapped it for a ported/polished factory one (90mm gold blade GM TB), and even tried a generic 103mm throttle body before as well. The 103mm TB, however, had other issues with tuning, that I think weren’t directly related to a possible throttle position re-learn.

[The_bald_eagle_machine]

Originally Posted by TheBrightSide

What exactly does the throttle position sensor re-learn exactly entail..? And like you, I’ve taken off my stock throttle body, swapped it for a ported/polished factory one (90mm gold blade GM TB), and even tried a generic 103mm throttle body before as well. The 103mm TB, however, had other issues with tuning, that I think weren’t directly related to a possible throttle position re-learn.

I have read that a relearn process is as simple as allowing the car to idle for 3 minutes, and it will adjust the idle automatically. OR... Driving at very specific mph for extended periods of time to set the TPS. It seems the general consensus is to just swap them out, no relearn is usually necessary.

[The_bald_eagle_machine]

Can anyone chime in here? Brand new GM Genuine throttle body. Same code. It shows sensor 1 TPS malfunction. Can anyone confirm if sensor 1 is the pedal? Or the throttle body? It looks like the issue is the 5v reference, of atleast that is what the scanner is showing is the "red" failure point. I'm not mechanically inclined enough to be able to read this properly... no cylinder misfires detected, and no injector misfires detected after roughly 1000 ignition cycles. I have the pedal coming in the mail tomorrow... so worst case scenario, I install that which should clear up this issue, I just want someone to tell me that is the problem. I like to learn from stuff like this so I want to understand what happened here and what the values mean.

[CamaroDreams76]

I think you narrowed it down honestly. If the TB is brand new AC Delco and you are still getting the same, has to be the pedal.

[The_bald_eagle_machine]

Man... this thing is throwing me for a loop. 1. Installed brand new GM Genuine throttle body. Still getting P0121 code. 2. Installed brand new GM Genuine throttle pedal assembly. Now it's throwing 12 codes all directly related to a fuel pump failure. Any thoughts on this?

[The_bald_eagle_machine]

Loading the parts cannon is starting to get quite expensive. Right now I'm about $700 deep on parts. I went ahead and ordered a new GM Genuine fuel pump assembly that has all the sensors and pressure regulator. I have this car set to be sold to a private buyer on the 27th and I really need to get it sorted.