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Thread: L84, E90 and DFM delete

  1. #1
    Tuner in Training
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    Sep 2016
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    L84, E90 and DFM delete

    I recently did a DFM delete on a 2019 Silverado with an L84 and E90 ECU. I sent the ECU to HP for the unlock service. When I received it back I installed it and started the truck prior to doing any tuning on it. It ran fine but of course threw CEL codes for DFM issues as the components were no longer present. I then plugged in and told it to ignore only the codes associated with the DFM so the CEL would go away and I set the DFM RPM to 0 so it never tries to turn it on. This was the only "tuning" that I did. When I check for CEL codes it is showing historical / pending / active codes for the DFM stuff and clearing them does not make them go away.

    My problem is... my inspection is expired and I'm trying to get it inspected, however some of the emissions checks are not going into a "ready" state and say "incomplete" even after a couple hundred miles of driving. I am thinking the codes are preventing some of the emissions checks from going to the "ready" state. Maybe it has zero to do with this but some of them items I didn't touch or do anything that should mess with their function.

    My question is... is there any way to mess with the ECU to get me to a state before the CEL codes were first thrown. I'm thinking if I would have tuned it before first start it wouldn't have ever thrown these DFM related codes that are sitting in the history.

  2. #2
    Just a heads up, I have a 23 Silverado and if you?re not flashing the ECM and TCM at the same time you will have to pull the ground off of the battery after every flash for the CEL to turn off completely. Don?t know if this is your issue but give it a go and lmk

  3. #3
    Tuner in Training
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    Post your tune. I'll compare it to when I did the delete on my 2020.

    Not all of the emissions checks will clear. They are not also all required to complete to pass.

  4. #4
    Tuner in Training
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    Quote Originally Posted by MeanMike View Post
    Post your tune. I'll compare it to when I did the delete on my 2020.

    Not all of the emissions checks will clear. They are not also all required to complete to pass.


    Will do when I get home later on. The checks that arent clearing arer o2 sensor heater, evaporative sys, fuel system, and heated catalyst. All things that have zero to do with DFM.

  5. #5
    Unplug the battery. Do you have a TCM p0700 code?

  6. #6
    Tuner in Training
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    Sep 2016
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    I figured it out guys, sorry for the confusion. For the DFM related codes you cant just uncheck the "SES Enable" box. You also have to set the Error Mode to "No Error Reported". Once I did that it allowed the remaining emissions systems to complete their check and go into 'READY" status. This may be common knowledge but I'm a newb and everything to do with this is a learning curve for me.

  7. #7
    Quote Originally Posted by DKjeep View Post
    I figured it out guys, sorry for the confusion. For the DFM related codes you cant just uncheck the "SES Enable" box. You also have to set the Error Mode to "No Error Reported". Once I did that it allowed the remaining emissions systems to complete their check and go into 'READY" status. This may be common knowledge but I'm a newb and everything to do with this is a learning curve for me.
    Oh Lmmfao.