It helps change setting in your computer. You will need it to recalculate your speedo if you regear or change tire size. You can also set what lights you want to be on during daytime running, set quick lane change signals. I bought it and used it when I changed out my stock wheels. Since I did not replace the air pressure sensors I used it to shut off the low pressure light on the dash. With my new jeep I will be using the new procal to lower my air pressure warning since will be generally running only about 33 lbs of air. I will let it go for $100 shipped. I can do Paypal if you send it as a gift.