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Thread: Part Throttle Transmission Shift tables - use pedal or ETC values?

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    Part Throttle Transmission Shift tables - use pedal or ETC values?

    I have a E39 ECM and a T43 TCM (2012 Impala, 3.6L V6, 6T70 transmission).

    I'm trying to understand what sensor the part-throttle transmission shift tables use for the 'Throttle Position (%)" axis in these tables. From what I've logged, it appears to be using the "ETC Pedal Average Position", but I've also read that it uses "Commanded ETC TPS".

    The reason that this is important is because if it uses the pedal position, then changes to the Driver Demand tables could thereby affect the transmission shift points, since you are modifying the amount of pedal travel needed. If the transmission tables use the "Commanded ETC TPS", then the first few columns of the transmission tables would be pretty much useless since the ETC TPS position is usually above 10% even when the pedal position is at 0%.

    Can anyone tell me what the "Throttle Position (%)" axis really represents in the part-throttle transmission tables?

    Thank you in advance!

  2. #2
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    Anyone??

  3. #3
    Tuner cp-the-nerd's Avatar
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    I expected someone to come in here and answer your simple question by now, but since they haven't I'll venture my educated guess/assumption that it refers to ETC values. I'd be happy for anyone to correct me if I'm wrong.
    2017 Chevy SS 6.2L/6M

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    Yeah, it's just not clear. From my logs, the shifts appear to match up with the average pedal position - and I think that the pedal position makes more sense, but since it's labeled as "Throttle Positon", it makes me wonder (if it were really pedal position, you'd thonk it would be labeled as such)...

    Would really liek to know for sure. Also, like I said, if it's really throttle position, then which one (in the scanner - there are about a dozen!)? If it truly is throttle-based, then the first few table columns would also be absolutely meaningless as I've never sen a throttle value below say 6%).

    I guess I should probably post in the V8 engine section since its a "generic" question and there isn't many people in the V6 secion!

  5. #5
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    After reviewing more logs, I'm convinced that the "Throttle %" axis in the Part Throttle shift tables is really using the "ETC Pedal Average Position" and not any of the throttle-related PIDs (ETC Position, ETC Desired Position, Throttle Position, Commanded ETC TPC, etc).

    Regardless whether it's a upshift, downshift or power downshift, it's obvious that the tables are acutally using the "ETC Pedal Average Position" for the "Throttle %" axis in the tables...

    At least on the E39/T43 ECM/TCM combo that is used in my vehicle.

  6. #6
    Tuner cp-the-nerd's Avatar
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    Good job sorting that one out on your own. That's a significant distinction to be aware of.
    2017 Chevy SS 6.2L/6M