Despite the host of impressive features, a Jeep can always be enhanced. Maybe you've put on larger tires and now the speedometer is off. Or the shift points seem sluggish. And now you have an annoying light on the dash telling you the tire pressure is not correct. Tinker long enough in a garage, and you'll know just how many things can go wrong. Fortunately, the AEV 30406007AG ProCal Module is a miraculous gadget that can assist with a wide variety of diagnostic problems. Intuitive and affordable, this product is built to activate daytime running lamps, temporarily increase engine idle speed for winching, provide a one-touch turn signal, clear engine codes, align the vehicle for ESP performance and more. Easy-to-use dip switches make operating the device a breeze. A simple code card is included; dial the correct code to begin a re-calibration. Once set, simply can plug the ProCal into the Jeep's OBD port and wait for the horn to honk. The process takes only a few minutes and can quickly be reversed if necessary.