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Thread: Need help with reading tcm

  1. #1
    Potential Tuner
    Join Date
    Jan 2021
    Posts
    1

    Need help with reading tcm

    I drive a 2020 sonic. I got hpt so I can tune the engine and trans. For some reason it won?t even give me a option to read the trans. I?ve reached out to hpt and they was quick to write me off and tell me it was unsupported but yet every Chevy sonic tcu before mine can be read? The trans hasn?t changed since the car was made in 2012. Is there something I?m doing wrong? I?m still new

    Thanks Zack

  2. #2
    If HPT says its unsupported, the program wont be able to access it. While the physical engine or trans may not have changed between 2019 and 2020, the programming in the ECM and TCM may have changed. GM is also making it extremely difficult to gain access to the newer control modules. An example of this would be the 8 speed transmissions. The transmissions are the same from 2015-19 but around 2017 GM switched the TCM from a T87 to a T87a which had more encryption that took longer for HPtuners to support.