Full Answer
Yes, and the order matters.
The correct sequence is to uninstall the Accessport before you do anything with ATLAS. Uninstalling returns the ECU to the factory map and releases the device from the vehicle it was married to. That leaves you with a car on its stock map and an Accessport you can sell or use on another vehicle.
Why this order rather than simply flashing over the top: the Accessport marries to a single VIN, and a device left married to a car you have moved on from is effectively a device you no longer own. If you skip the uninstall and later sell the car, you have sold the Accessport with it. Uninstalling first protects several hundred dollars of resale value.
Once the car is back on its stock map, treat ATLAS setup as a fresh start rather than a migration. Read the ECU and save your factory file as a backup - this is now genuinely your own baseline rather than something a previous flash left behind. Datalog before you write anything, both to prove your adapter and connection work and to see what the stock car does. Then flash when you are ready.
One thing that does not transfer: your Accessport maps. Off-the-shelf maps are built for a specific platform and are not portable between tuning ecosystems. If you were running a custom map from a tuner, ask whether they work with ATLAS - many tuners support multiple platforms, but the file itself is not something you can simply move across.
What does transfer is everything you learned. Your understanding of what your car does, which hardware is on it, and what your logs normally look like is all still valid.
A final note that applies regardless of direction: switching platforms does not erase anything. The ECU retains a record that reflashes occurred, whichever software performed them, and returning to stock removes the map rather than the history.
Last updated 8/20/2026