Keyless Entry System Description and Operation - Passive

Passive keyless entry allows entry to a locked vehicle without pressing any buttons on the keyless entry transmitter. You must only have the transmitter with you. This passive system is also part of the vehicle starting system. It allows you to start and run the vehicle having only the transmitter as your key. The passive entry and starting system use low frequency antennas in 5 different areas on the vehicle to determine the location of the transmitter. When passively opening a locked door or the rear compartment lid, you must have a programmed transmitter with you in your pocket, purse, or briefcase. As a customer opens the door handle or presses rear compartment touch pad, the low frequency antenna sends out a challenge to the keyless entry transmitter. The transmitter must be in a one meter range of the door or rear compartment lid in order to receive the challenge. If the challenge is met, the transmitter will respond, allowing the door to be unlocked and opened.

Starting the vehicle also works in much the same manner. The key fob must be within the passenger compartment of the vehicle when the START/ACC/OFF button is pressed. The low frequency antenna sends a challenge to the transmitter and if the challenge is met, the transmitter will respond to the RCDLR. The RCDLR will then send out a fuel enable password to the engine control module (ECM). As long as all security requirements are met, and the ECM receives the password over the serial data line, the engine will start and run. A low transmitter battery or radio frequency (RF) interference from aftermarket devices, such as 2-way radios, power inverters, computers, etc., may cause a system malfunction. High RF traffic areas, such as gas stations that use pay-at-the-pump RF transponders, may also cause interference that could lead to a malfunction.