JK ProCal ModuleAEV's ProCal Module is a hand held powerhouse! This essential tool provides JK owners an easy, low cost way to make a variety of useful changes not offered by the dealer or any other re programmer. Topping the list is the ability to correct the speedometer and gear ratio when larger tires are installed. When the speedometer is left uncorrected, there is a major degradation in the performance of the stability control (ESP), transmission shifting, and