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Thread: E38 flash disables TCM help!

  1. #1
    Member SPi's Avatar
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    Default E38 flash disables TCM help!

    I have a 2008 C6 Corvette LS3 Auto in the shop for some simple mods and a tune. I am having an issue I have never come across before. Anytime I flash a tune into the ECM that is not the stock tune I lose the transmission. By lose the trans I mean it goes into limp mode right after an ECM flash, i cannot communicate with the TCM and it does not set any codes. This happens with a cal and a full flash. If I flash the stock tune into the ECM the transmission comes back to life and everything is fine, but only on the stock tune. I have tested and if I even change one parameter in the stock tune and flash it I lose the trans. This is driving me crazy, hoping somebody has run across this before. All my software is up to date. I have installed longtube headers and a cold air and need to get this thing tuned. Any ideas would be great. I have attached the stock ECM and TCM files


    Hertz TCM.ctz
    Hertz C6 LS3.ctz

  2. #2
    Member SPi's Avatar
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    Thought I should update this very odd problem. After way too much trial and error I was able to figure out what was causing my problem. I have no idea why but as long as I don't change B2501 at all then everything works fine and I can flash and tune the car. If I change B2501 at all I lose the trans after I flash the engine. Can anyone shed some light on this? Almost didn't want to post up the solution because it make no sense, but thought just in case somebody runs across this I better.

  3. #3
    Joe (Moderator) joecar's Avatar
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    B2501 = TCS Max Engine Torque

    I don't know for sure, but maybe the ECM and TCS now converse intensely so the TCM can't get on the CAN bus.

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