In this tutorial I will explain in steps, for how to correct the checksum after editing a GM module calibration file.
This process illustrates correcting the checksum for the first four bytes.
It's beneficial to read up on these other tutorial to familiarise yourself with GM's calibration files concept if you're new.
Tools you will need.
Open the calibration file in Neo and edit your file.
Set Predefined Layouts as Expert User Layout.
Select all the codes in the calibration file except the first four bytes/code.
At the bottom of Neo click Checksum.
In Neo's checksum window, change the option: Whole document to Selection only.
Select Sum of Big-Endian 16-bit value
Click the Refresh button.
Copy the last 4 digits, which is: 9730
Convert 9730 into Binary code, then copy paste the binary code in a text editor.
Now you need to create a reverse copy of the binary code: 1001011100110000, see the example below.
Convert the reverse binary code 0110100011001111 into hexadecimal code, which equals to 68cf
Now you need to add 1 to the hexadecimal code, which looks like this 68cf+1=
Use this online calculator to do the calculation.
Now you have 68d0
Replace the first four unselected bytes/code in the calibration file with 68d0.
The checksum has been corrected.
Save the calibration file and program your calibration package to the module using GM DPS.