To program a keyless entry system for a Jeep Grand Cherokee, special equipment must be connected to the automobile for programming purposes. Therefore, programming cannot be facilitated without the assistance of a locksmith or a local Jeep dealer. No onboard programming process exists for programming keyless entry systems for Jeep Grand Cherokees manufactured from 1996 to 2004.
Keyless entry systems are made with a miniature chip that creates a code and a pea-sized transmitter that sends the signal. A rolling code is used for security. Therefore, a system that features 40 bits of rolling code supplies around 1 trillion possible codes.
The controller chip's memory in the transmitter is the holding spot for the 40-bit code. When the button on a keyless entry fob is pressed, it transmits the code in addition to a function code to perform an operation. The code may instruct the vehicle to unlock or lock the doors or open the trunk. In response, a controller chip in a receiver also holds the 40-bit code in its memory.
Remotes that allow for keyless entry are also known as SMART keys. The entry systems not only open car doors, they can be programmed to roll down car windows or open the sunroof. Electronic equipment or headlights can be switched on as well. In some models of autos, keyless entry systems feature a sensor that prevents a driver from locking his keys in the car.