So is this an issue with all the 2021 GM vehicles or what? I'd dealing with a truck but wonder if the cars are like this too. You can scan via the OBD port but can't write to the ECU. I had to make a ECU wiring harness to plug directly into the ECU to write to it. This is driving me nuts. Takes me 10-15min every time I reflash this vehicle. Is everyone having this issue on all 2021's?