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Thread: E92A ECM Swap Question

  1. #1
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    E92A ECM Swap Question

    2018 L86 with a 10L80. I Keep randomly throwing a P2135 check engine code which puts the engine into limp mode. I recently noticed that the fuel trims will go between 10-14% lean. I've checked all the grounds, tried a new peddle, all of the harness wires are basically brand new, and all connections are good. At this point, I'm leaning towards it being an ECM issue.

    My question is, if I buy an ECM, do I have to get it programmed to work with the TCM, or will it be plug-and-play? What other considerations do I need to keep in mind if I want to get another ECM?

  2. #2
    Advanced Tuner Shrek's Avatar
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    The old adage that "the Devil is in the details" definitely applies to Gen 5 conversions.

    A couple of quick things to check ....

    A potential component mismatch - is the calibration in the E92A ECM, the throttle body, and the accelerator pedal (APP) all for the same specific vehicle ?

    A potential power cycling issue - do the ECM and TCM shut down (power down) at the exact same time ?

    If you did not wire all of the ECM and TCM ignition voltage feeds to the same switched circuit - then one of the modules may be still "on" after the other has powered down (i.e. is no longer on the CanBus network) - which may cause various issues to manifest.

  3. #3
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    Answers in line below in red.

    Quote Originally Posted by Shrek View Post
    The old adage that "the Devil is in the details" definitely applies to Gen 5 conversions.

    A couple of quick things to check ....

    A potential component mismatch - is the calibration in the E92A ECM, the throttle body, and the accelerator pedal (APP) all for the same specific vehicle ? No to all of these. Brand new APP, TB came on the engine that came from a donor vehicle, ECM came from company I bought the swap kit from.

    A potential power cycling issue - do the ECM and TCM shut down (power down) at the exact same time ? It happens while I'm driving and at no particular time. It will just happen randomly and cause the engine to go into limp.

    If you did not wire all of the ECM and TCM ignition voltage feeds to the same switched circuit - then one of the modules may be still "on" after the other has powered down (i.e. is no longer on the CanBus network) - which may cause various issues to manifest.Harness came from the swap company and others seem to be running it just fine, but I don't know exactly how it's wired.

  4. #4
    Advanced Tuner Shrek's Avatar
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    This is not an answer to my question ....


    Quote Originally Posted by CerealKiller19 View Post
    ... No to all of these. Brand new APP, TB came on the engine that came from a donor vehicle, ECM came from company I bought the swap kit from ...

    These all need to be specifically matched components.

    You cannot use just any APP, nor can you use just any ECM calibration.

    You may have a components mismatch.

  5. #5
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    They all match the donor vehicles part numbers and are all GM parts, not off-brand from the parts store.

  6. #6
    Advanced Tuner Shrek's Avatar
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    So ... using the VIN from the donor vehicle ...

    The calibration in the E92A ECM is correct - and you have confirmed this by entering the donor vehicle VIN in GM's calibration website and verifying all segments ?

    The APP (pedal) is correct ?

    GM sometimes (not always) specified a different APP between 6L80 platforms, 8L90 platforms, and 10L90 platforms.

  7. #7
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    So, I did a little more research and all of the part numbers match what was in the donor cars.

    I've replaced the pigtail at the APP and still have the issue.

    The last 3 things is could be are the ECM, Thottle Body pigtail, or the Throttle Body itself.