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Thread: HPT Scan "Unknown" Value In Trans Current Gear Channel

  1. #1
    Potential Tuner
    Join Date
    Jan 2019
    Posts
    1

    HPT Scan "Unknown" Value In Trans Current Gear Channel

    Recently converted to HPT (2010 Challenger 426 stroker,ProCharger, NAG-1 5 speed auto, 2800 stall converter)

    On my scan logs I notice the "unknown 02.69.00...." value in the Trans Current Gear Channel. Low to part throttle. Attached scan file shows unknown value in the 1-2 and 2-3 shifts. Lasts .4-.6 seconds. I don't know if it is related, but the car experiences a momentary stumble, goes flat, then back to normal at about the same time as these shifts occur? Otherwise car seems to run fine.

    Has anyone experienced similar conditions? Thanks
    Attached Files Attached Files

  2. #2
    Senior Tuner
    Join Date
    May 2015
    Posts
    1,859
    That's your torque converter locking/unlocking. There is a correlation between engine rpm and output shaft rpm that helps the TCM know what gear your in, but with the converter unlocked now the engine is revving all over the place and not correlating between tire speed, trans output shaft, and engine rpm. So just says unknown for a second.