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Home >> Saturn >> 2009 >> Vue Red Line, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 570 (Keyless Entry System And Remote Functions) >> Description and Operation >> Keyless Entry System Description and Operation >> Keyless Entry System Description and Operation - Passive
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Keyless Entry System Description and Operation - Passive

WARNING: This page is about a different car, the 2007 Cadillac XLR. However, it is still accessible from the selected car via links, so may be relevant.

The passive keyless entry allows you to enter a locked vehicle without pressing any button on the key fob transmitter. You must only have the fob 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 fob as your key. The passive entry and starting system use low frequency antennas in 4 different areas on the vehicle to determine the location of the key fob to the vehicle. When passively opening a locked door or a rear compartment lid, you must have a programed key fob with you in your pocket/purse/breifcase. As a customer presses an exterior door handle switch or exterior rear compartment lid release switch, the low frequency antenna sends out a challenge to the key fob. The key fob must be in a one meter range of the door or rear compartment lid that the customer is opening in order to receive the challenge. If the challenge from the low frequency antenna is met, the key fob will respond to the remote control door lock receiver (RCDLR) via a radio frequency signal allowing the door to be unlocked and opened. Starting the vehicle also works in 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 key fob and if the challenge is met, the fob 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, cellular phone chargers, computers, etc. may cause a system malfunction. High RF traffic areas, such as gas stations which use pay-at-the-pump RF transponders, may also cause interference that could lead to a malfunction.

The passive keyless entry has the following components: