TPS Issue

[Neuner]

Wasn't sure if this belonged here or in the Engine / Drivetrain so please move if needed. However, I would appreciate the attention as I am unable to find a resolution to this common problem.

'14 Suburban LT, 2wd.

Got the familiar p2127 error code;

• Faulty Accelerator Pedal Position Sensor
• Accelerator Pedal Position Sensor harness is open or shorted
• Accelerator Pedal Position Sensor circuit poor electrical connection
• Faulty Engine Control Module (ECM)

After the 1st occurrence, I replaced the pedal assembly with GM OEM early last year. Went awhile before acting up and thought it was a fluke. Then it would be a month or 2 before code was thrown. Now it's every day, even multiple times a day.

Nothing has been consistent to give me any hints. Issue happens while traveling fast or slow, pedal pressed or not even a foot on the pedal, smooth or bumpy road.

Been hard to review because it's been happening at the worst time and I have to clear the code to make it home.

I've inspected the wiring and connections and all looks great.

Searched heavily and found this situation quite common but haven't found a definitive resolution yet. Others have replaced almost everything except the ECM and still have the same.

Anyone know for sure the culprit?

 

[Geotrash]

Wasn't sure if this belonged here or in the Engine / Drivetrain so please move if needed. However, I would appreciate the attention as I am unable to find a resolution to this common problem.

'14 Suburban LT, 2wd.

Got the familiar p2127 error code;

• Faulty Accelerator Pedal Position Sensor
• Accelerator Pedal Position Sensor harness is open or shorted
• Accelerator Pedal Position Sensor circuit poor electrical connection
• Faulty Engine Control Module (ECM)

After the 1st occurrence, I replaced the pedal assembly with GM OEM early last year. Went awhile before acting up and thought it was a fluke. Then it would be a month or 2 before code was thrown. Now it's every day, even multiple times a day.

Nothing has been consistent to give me any hints. Issue happens while traveling fast or slow, pedal pressed or not even a foot on the pedal, smooth or bumpy road.

Been hard to review because it's been happening at the worst time and I have to clear the code to make it home.

I've inspected the wiring and connections and all looks great.

Searched heavily and found this situation quite common but haven't found a definitive resolution yet. Others have replaced almost everything except the ECM and still have the same.

Anyone know for sure the culprit?

Do you have access to a Tech2? If so, have you used it to test for proper throttle-opening and throttle-closing range? There is a readout in the tool that will tell you what the pedal is communicating to the ECU. That's the test procedure for it at least.

 

[Neuner]

Do you have access to a Tech2? If so, have you used it to test for proper throttle-opening and throttle-closing range? There is a readout in the tool that will tell you what the pedal is communicating to the ECU. That's the test procedure for it at least.

I do not. I use a simple OBDII with the Torque Pro app.

I'll need to research as I'm not familiar. Any suggestions? Thank you for the response.

 

[Geotrash]

I do not. I use a simple OBDII with the Torque Pro app.

I'll need to research as I'm not familiar. Any suggestions? Thank you for the response.

It's the dealer-level tool for doing deep systems diagnosis and resets in areas not covered by run-of-the-mill generic OBII scanners. Most of us have Chinese-made knock-offs of them from chinacardiags.com: https://www.chinacardiags.com/whole...el-suzuki-isuzu-holden-with-full-package.html

Also, there is a sticky thread containing the list of people who have them and will let you use it if you happen to live nearby.

 

[Neuner]

Thanks. It's one of those teeter-totter questions. Buy tool + find out you have to pay $1XX to replace the TPS anyways or replace the TPS, have it still act up and spend a lot more trying to resolve it in pieces because you don't have a Tech2.

Being a newb with one of those, how hard will it be for me to figure out how to read the output to diagnose? Is it a big learning curve?

 

[Geotrash]

Thanks. It's one of those teeter-totter questions. Buy tool + find out you have to pay $1XX to replace the TPS anyways or replace the TPS, have it still act up and spend a lot more trying to resolve it in pieces because you don't have a Tech2.

Being a newb with one of those, how hard will it be for me to figure out how to read the output to diagnose? Is it a big learning curve?

No, it's super easy to use. Totally menu-driven. If you're going to own one of these trucks for a few years, it'll save you money.

 

[Neuner]

Had to go out of town and got a stomach bug so haven't done anything.

The replacement pedal I got was from Mexico and so I started searching. Found reviews of others stating that their "Made in Mexico" pedal assemblies failed after only about 6 mos of use.

I'm now searching for one that is made elsewhere.

 

[NT Automotive]

Based on the thread title I for some reason thought this was a tpms thread but obviously not.

Very interested in this thread bc we sell throttle controllers (among other things) and looking to sell them to all 2007+ tahoe/yukon owners very soon...but will now require a disclaimer.

Additionally. I will ask some of the pedal assembly engineers I work with about your problem and report back if any useful feedback provided.

For now sounds like made in mehico is made to break. Is there not a USA made supplier?

 

[Neuner]

The new Pedal Assembly I picked up was the exact same. Made in Mexico but with the GM Stamp/Sticker.

Replaced it and made a small errand. Going over a speed bump it threw the code again and went into limp mode.

It can't be the pedal. I'm really thinking it's a loose connection someplace. Maybe even at the pedal connector, because I've noticed that this has primarily occurred when I've hit a bump.

1st time it happened was after I floored it getting on the highway. No bump but the pedal assembly is flimsy enough that it could have flexed and caused a bad connection at the plug?

I want to review all of the related wiring looms and connectors but I can't find a wiring schematic for the pedal. Anyone have one? I don't think the Chilton type books contain one.

 

[Fless]

Wondering if it's still the P2127 code. Can you get the current code and look at freeze frame data (when the code sets) on a scanner? That would give you some data points to compare.

 

[drakon543]

im not sure exactly about this issue but i did some research on a similar issue for a work buddy through some of my contacts. anyway similar issue but im unsure of the codes he was getting. replaced the pedal position twice and the tb twice to alleviate the issue. 2 different shops were doing to work on his silverado. according to the p/n both parts are the same so issue may be similar. there's 2 ways to do the relearn on both parts of the throttle/pedal circuit. a simple unhooked battery for 15 or so minutes may cause the ecm to force a relearn but doesn't always work. a tech2 or a snapon obd2 scanner has the function to trigger a relearn on the position. far as i recall the ecm freaks if it doesn't see matching position movement between the pedal and throttle. if you had the battery unhooked for atleast 15 min while you were doing this work it may actually be the tb or the pedal relearn didn't get triggered. find someone with the necessary scanner to trigger a relearn and that may help. guy at work has been goint 2 yrs with no further issues tho.

 

[Neuner]

replaced the pedal position twice and the tb twice to alleviate the issue.

a tech2 or a snapon obd2 scanner has the function to trigger a relearn on the position. far as i recall the ecm freaks if it doesn't see matching position movement between the pedal and throttle.

Thanks for the suggestion! Didn't know about a relearn. I downloaded and used an app that specifically resets the throttle. All of the dash lights came on and it said complete. Never seen that before. Anyways, going to move forward with one thing at a time. If this doesn't work, going to look into replacing either the throttle body or the connectors.

Anyone know the OEM of the TB? Is it ACDelco like the pedal?

 

[drakon543]

if there's an option for acdelco you can generally just default to that. i dont think there was much that gm wouldn't use acdelco if they had that as an option.

 

[Fless]

Thanks for the suggestion! Didn't know about a relearn. I downloaded and used an app that specifically resets the throttle. All of the dash lights came on and it said complete. Never seen that before. Anyways, going to move forward with one thing at a time. If this doesn't work, going to look into replacing either the throttle body or the connectors.

Anyone know the OEM of the TB? Is it ACDelco like the pedal?

Your best bet is to first find the "GM Genuine part" or "ACDelco Original Equipment" wording. While that part could be made by Delphi, AC Delco, or another manufacturer, it's what came on your truck. Should be worded like this one from RockAuto:

From the GMParts.com website (ranked in order of quality):

ACDelco has one more line, "ACDelco Advantage" but that's like any other aftermarket parts line, a crap shoot at best. Avoid it if possible.

 

[Doubeleive]

Thanks for the suggestion! Didn't know about a relearn. I downloaded and used an app that specifically resets the throttle. All of the dash lights came on and it said complete. Never seen that before. Anyways, going to move forward with one thing at a time. If this doesn't work, going to look into replacing either the throttle body or the connectors.

Anyone know the OEM of the TB? Is it ACDelco like the pedal?

what app? and what tool was used for obd communication with said app?

 

[Neuner]

As I went several days without issue, I thought I had it. Longest I had gone in a while. This morning it triggered again as I pulled into work. Checked connections, removed and reconnected them and no change.

Next up I guess is to replace the throttle body.

Found: Genuine GM 12629992 Throttle Body (ACDelco GM OE)

 

[Neuner]

Is the Tech2 the only way for us to trigger the relearn for the Throttle Position?

I also have a Toyota Sienna that's needing it as well. Would be great if there was a scanner that performed this function for both like the Launch CRP129E

Local shop will perform the reset for $80 each but I'd rather have one of these cheap scanners instead if it will work just for this purpose.

 

[Doubeleive]

Is the Tech2 the only way for us to trigger the relearn for the Throttle Position?

I also have a Toyota Sienna that's needing it as well. Would be great if there was a scanner that performed this function for both like the Launch CRP129E

Local shop will perform the reset for $80 each but I'd rather have one of these cheap scanners instead if it will work just for this purpose.

I have never used this brand but it should work

 

[Neuner]

Slow boat from China and they sent me a used one even though I ordered new. Box opened, missing charger cord, and finger prints all over it. Even had the PO email and contact info stored. Going to return.

Wouldn't trigger a relearn but was able to pull some diagnostic data that I wasn't able to before;

Power System:
1. Control Module Communications Bus A Off
Safety and Security System:
1. Lost Communication With Body Control Module
2. CAN Bus Communication
3. Lost Communication With Engine Control Module
4. Lost Communication With Transmission Control Module
Electronic Brake Control Module:
U0140-00 Lost Communication With Body Control Module
U2100-00 CAN Bus Communication
U0100-00 Lost Communication With Engine Control Module
U0101-00 Lost Communication With Transmission Control Module
Engine Control Module:
U0073-00 Control Module Communication Bus A Off


Can this be the culprit to my overall issue? Bad cable or connection? I want to look into replacing the cable but not sure where to begin or how far the loom extends. Better to have a shop do it?

BTW, the battery was dead from the vehicle sitting for so long which I read might trigger one or more of these codes so it's hard to tell.

 

[Foggy]

Most of those are "ghost codes" as I call them..
They can be triggered by a low/disconnected battery or really almost anything
in the history...
I clear all this crap out.. Then get in a few drive cycles to really see what going on...
Don't put any effort into those codes unless a specific one comes back..
you'll need at least 3 full drive cycles and then recheck