The engine didn’t explode. The ECU didn’t die. Marcus closed the tool, disconnected the cable, and said, “Crank it.”
These are standalone devices that plug into the OBD-II port. ls1 flash tool
Your choice depends on your goal:
A: If your car is over 20 years old, there is no warranty. On newer crate engines? Yes, GM will deny warranty claims if they detect a non-GM flash checksum. The engine didn’t explode