The days of counting teeth in speedometer drives to correct for gear ratio changes and tire size are long gone. The electronic age has arrived and has made dialing in our Jeep JK Wranglers much easier, if we have the right tools.
One of those tools is the American Expedition Vehicles' (AEV) ProCal Module. The ProCal allows easy calibration of gear ratio, tire size, the tire pressure threshold of the TPMS, and other useful functions. The ProCal Module uses DIP switches to program settings, just like our older analog garage door openers did for security settings. The nine switches are pushed either up or down in sequence to program. The first three switches set the function being addressed, while the next six are set according to the programming needed. It sounds much more complicated than it is.
The ProCal allows calibration of tire sizes from 24 to 54 inches in diameter and gear ratios from 3.07:1 to 5.67:1. These ranges are much greater than any other JK programmer on the market today. It's important that the JK's PCM know the correct tire diameter and gear ratio because, as AEV puts it, "The ESP uses vehicle speed along with individual sensors that measure acceleration both front to rear and side to side.ESP functions by calculating how much steering angle the user inputs and how fast the vehicle is going and can therefore calculate how much side to side acceleration should occur. If the side to side acceleration is less than what the ESP predicts, that means the vehicle is sliding (just like you can feel when a vehicle is sliding) and it will try to correct the situation by applying specific brakes at each wheel and/or reducing throttle. If the tire size and gear ratio values are incorrect, the calculations the ESP system processes will also be incorrect. Lifted vehicles are more prone to inadvertent ESP activation, because most either do not have the steering wheel centered, the speedometer is wrong, or the steering has been modified in such a way to change the ESP parameters."
The Tire Pressure Monitoring System (TPMS) mandated by Federal law is a giant pain for those of us who run low pressure off-road or want to run optimal highway pressure. The ProCal allows setting the threshold where the TPMS sounds an alarm anywhere from 0 to 31 psi. If set at 0 psi, the ProCal turns off the TPMS, which kills the warning light and chime completely. This is great! Now, we no longer have to run the factory-required 37 psi, or the metal valve stems with the TPMS senders if we want the warning light and chime to stay off.
JK Wranglers have a one-touch lane change feature where the signal flashes three times with just a touch of the turn signal stalk. We like this feature, but if you don't, you can disable it with the ProCal. Daytime running lamps can be turned on and can be set to run high beams, low beams, parking lights, European setting (whatever that is), or off. If you've removed your SmartBar -- the Rubicon electronic swaybar -- the swaybar light on your dash stays on. The ProCal can deactivate the SmartBar system to eliminate the warning light.
When you replace the PCM, such as in a Hemi swap, the JK's drive-by-wire throttle has to be recalibrated and paired with the PCM. You can perform this function with the ProCal. The ProCal can also set up a new PCM with your vehicle's V.I.N. so the PCM will work. Diagnostic Trouble Codes can be cleared with the ProCal.
If you winch or weld in the field, you know that the JK's idle speed is really too low for power-sensitive tools. You can temporarily raise the JK's idle speed up to 2,000 rpm with the ProCal. After ten minutes, if not reset, the idle will return to normal.