ABS/Stabil Trak Lights turned on and intermittently goes into reduced power/limp mode when trying to accelerate?

AKRAFT22

MEMBER
2011 CHEVROLET EQUINOX
3.0L
6 CYL
2WD
AUTOMATIC
95,000 MILES

The vehicle listed above has ABS/Stabil Trak lights on dashboard and will occasionally go into reduced power/limp mode when trying to accelerate. I have had two mechanics look at the car and have been given two different solutions to the problem. I will attach the DTC for further information. One mechanic checked all the wiring (did not indicate what wires) and didn't find any issues to his knowledge.

So far, the accelerator pedal has been replaced, which did not resolve the issue. The mechanic shared that when monitoring real time data when driving, there did not seem to be any issue with the accelerator pedal sensors. The sense is that the computer module may be the cause of the issue, however, the question is which one? I've been told both the ECM and the EBCM. Any insight you could share would be great!

I'm not sure if the file uploaded, therefore, will share the codes here (3 faults):
1. Engine Control Module Code: P2138:00
2. Electronic Brake Control Module Codes: C056D:00; U010:71

Thanks!

3 Replies

KEN L

MASTER CERTIFIED MECHANIC
42,935 POSTS

I would start by checking all fuses with the system on. I see there is a fuse F36DA 7.5 amp that helps run the CAN which is located on the interior fuse panel (center console). Here are the wiring diagrams for the CAN so you can see how the system works:

https://www.2carpros.com/articles/how-to-check-a-car-fuse

If the fuse is good, it could be either one, the PCM or EBCM. I would remove them both and have them tested. But I have seen a bad throttle body actuator cause the limp mode issue and it may affect the other modules as well. Though it does leave a code any glitch in the throttle system will cause limp mode.

P2138: This code points to a problem with the throttle/pedal position sensor/switch D/E voltage correlation. It usually indicates an issue with the throttle position sensor (TPS) or the accelerator pedal position sensor (APP). This code may result in reduced engine power or the vehicle going into a "limp mode" to protect the engine. Possible causes include a faulty TPS or APP sensor, a wiring issue, or a problem with the electronic throttle control system.

C056D: This code indicates a problem with the electronic brake control module (EBCM) or the brake pressure sensor. It could be related to issues with the ABS (anti-lock braking system) or the stability control system. Possible causes include a malfunctioning EBCM, a faulty brake pressure sensor, or wiring/connectivity problems.

U010: This code refers to a communication problem with the transmission control module (TCM). It suggests that there might be an issue with the communication network between the TCM and other modules in the vehicle. This could be caused by a faulty TCM, wiring problems, or a problem with the CAN (Controller Area Network) bus system.

Here is how to change out the actuator and remove the PCM and EBCM. Check out the images (below). Please let us know how it goes

Images (Click to make bigger)

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Monday, July 17th, 2023 AT 11:52 AM

AKRAFT22

MEMBER
2 POSTS

Thank you for all your suggestions for resolving the issue. From the last posting, we did end up replacing the ECM. This resolved all the performance issues it was having are, poor idle, reduced power, etc. The only issue currently is that the Abs, Stability Trak, and brake lights are on the dash. The car has been driven and seems to run great and has not had any braking issues yet. The check engine light is not on, and we are not able to pull any default codes with a basic OBD scanner tool. We are assuming it now comes down to replacing the EBCM. Your thoughts and knowledge are greatly appreciated.

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Monday, August 21st, 2023 AT 1:41 PM

KEN L

MASTER CERTIFIED MECHANIC
42,935 POSTS

I would do a CAN scan to help confirm the issue. You can get a CAN scanner (Controller Area Network) which will work on most cars from Amazon.

Here is a video to show you how:

https://youtu.be/u-4syLc-ifQ

and

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

Here is one for about $99.00 if you need it:

https://amzn.to/3ZixY4v

Here is how to change the BCM out, you can get a preprogrammed unit by searching Google or Ebay. Check out the images (below). Please let us know what happens.

Images (Click to make bigger)