# Clearing the U029E code



## v65rider (Dec 2, 2019)

Has anyone ever been able to clear the U029E code to clear when limited to 4mph? I have replaced the NOX2 sensor and can even see it working when I run test using Gretio. However I am still seeing the U029E code and can't get it to clear.


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## 15cruzediesel (Sep 30, 2019)

Welp based on the overwhelmingly amount of responses I'll say this must be a first error code we have delt with.

Sooooo

1) why did you change the sensor. Codes ect ect
2) did you use a GM replacement
3) did you do a nox relearn


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## ChevyGuy (Dec 13, 2014)

Is it unable to clear or does it come back? I'm wondering if the problem is the scanner doesn't know how to clear it. See if you can find a better scanner.


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## v65rider (Dec 2, 2019)

15cruzediesel said:


> Welp based on the overwhelmingly amount of responses I'll say this must be a first error code we have delt with.
> 
> Sooooo
> 
> ...


Yes I replaced the sensor and yes 
Ho do you do a nox relearn?


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## v65rider (Dec 2, 2019)

ChevyGuy said:


> Is it unable to clear or does it come back? I'm wondering if the problem is the scanner doesn't know how to clear it. See if you can find a better scanner.


I believe it is unable to clear it?


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## 15cruzediesel (Sep 30, 2019)

v65rider said:


> Yes I replaced the sensor and yes
> Ho do you do a nox relearn?


Should be an option in Gretio engine module.


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## Detrious (Jul 5, 2017)

There is also a reductant system malfunction service bay test under engine module tests, you can try that one as well.


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## v65rider (Dec 2, 2019)

Detrious said:


> There is also a reductant system malfunction service bay test under engine module tests, you can try that one as well.


Thank you! I will find and try them! Right now I have a car that I can't drive.


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## Snipesy (Dec 7, 2015)

v65rider said:


> Thank you! I will find and try them! Right now I have a car that I can't drive.


Make sure to run the heaters before hand. As outlined here where it goes over the RSMWSBT








Emissions Supplemental Repair Guide


Surreal Development’s General Motors Emissions Diagnostic Guide This document is intended to be supplementary guidance based on Surreal Development’s own knowledge of GM diesel engines. This document is made to be a reference in tandem with OEM service manuals and is not made to be a replacemen...




docs.google.com





Depending on failure it may or may not be important. Skipping it can cause the test to hang.


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## v65rider (Dec 2, 2019)

15cruzediesel said:


> Should be an option in Gretio engine module.


I do not have that option under the engine module. I only have three options under general engine controls. Wait to start lamp, MIL Lamp, Desired Idle. It is also not listed under the Advanced Diesel Engine Controls


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## v65rider (Dec 2, 2019)

Snipesy said:


> Make sure to run the heaters before hand. As outlined here where it goes over the RSMWSBT
> 
> 
> 
> ...


I have made sure to run the heaters before hand as instructed.


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## 15cruzediesel (Sep 30, 2019)

v65rider said:


> I do not have that option under the engine module. I only have three options under general engine controls. Wait to start lamp, MIL Lamp, Desired Idle. It is also not listed under the Advanced Diesel Engine Controls


Should be there. It is important to clear any codes before running tests when possible or it might not complete the test.


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## Snipesy (Dec 7, 2015)

You can try clearing codes with Torque. Gretio is UDS and that sometimes changes things.

TLDR: OBD2 is not the same as UDS.

Just fair warning this doesn’t clear the DTC on the backend. It just stops it from lighting up. For a DTC to 100% clear it must be removed from the “Testing” DTCs list within Gretio.

There is no way to reset testing DTCs.


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