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Home >> Chevrolet >> 2017 >> Spark ACTIV, Automatic CVT Trans >> Repair and Diagnosis (Single Page) >> Transmission >> Automatic Trans >> Automatic Transmission - JATCO CVT >> Diagnostic Information and Procedures >> DTC P1790: Transmission Control Module Checksum Error - ROM Assembly >> Circuit/System Verification
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Circuit/System Verification

  1. Ignition OFF for at least one minute to allow for the complete shutdown of the K71 Transmission Control Module.
    NOTE: If the TCM is not completely shut down, this procedure may not complete properly. It may also be necessary to physically disconnect the scan tool from the vehicle to ensure complete power down.
  2. Ignition ON.
  3. Using the scan tool, perform the Transmission Adaptive Pressure Reset. Refer to Transmission Service Fast Learn Procedure (MR8) 
  4. Clear the DTCs.
  5. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data. The DTC should not set.

    Verify DTC P1790 is not set.

    • Test failed 1 time(s) If the DTC sets 

      Refer to Step 1

    • Test failed 2 time(s) If the DTC sets 

      Replace the component: Q8 Control Solenoid Valve Assembly

    • If the DTC does not set 
  6. All OK.
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