Keyless Entry System Description and Operation (without ATH)
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Keyless Entry System Description and Operation (without ATH)
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Keyless Entry System Description and Operation
The keyless entry system is a vehicle entry device. The keyless entry system is used in conjunction with the door locks to unlock the vehicle. Keyless entry will lock/unlock the vehicle doors or open the rear compartment lid when a corresponding button on the keyless entry transmitter is pressed. This is achieved by the key transmitter sending a radio signal to the receiver antenna of the keyless entry door lock which has a direct link to the BCM. The BCM interprets the signal and activates the requested function or request the appropriate control module to activate the function via a serial data message. A low transmitter battery or radio frequency interference from aftermarket devices, such as 2-way radios, power inverters, computers, etc., may cause a system malfunction. High radio frequency traffic areas, such as gas stations that use pay-at-the-pump radio frequency transponders, may also cause interference that could lead to a malfunction. Keyless entry allows you to operate the following features:
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Power liftgate, if equipped
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Illuminated entry lamps
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Panic alarm/Vehicle locator
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Keyless Entry System Description and Operation - Keyless Start
The keyless start portion of the keyless entry system allows vehicle starting, having only the transmitter as your key. The keyless start system use low frequency antennas in three different locations on the vehicle to determine the location of the transmitter. Multiple antenna are used to ensure complete coverage of the vehicle interior and rear compartment. When using the keyless start system, a programmed transmitter must be in the vehicle's interior, in the driver's pocket, purse, or briefcase.
When the ignition mode switch is pressed, the low frequency antennas emit a challenge to the keyless entry transmitter. The transmitter receives this challenge and emits it's response as an RF message, which is received by the remote control door lock receiver. If the response is correct, vehicle starting will be allowed. If RF communication is interrupted, a "No Remote Detected" message will be displayed on the DIC. In these cases, the transmitter can be placed in the transmitter pocket located in the center console, under the storage tray. The immobilizer antenna coil is located directly beneath the transmitter pocket. Placing the transmitter in the pocket will create a low powered coupling between the transmitter and immobilizer antenna, allowing communications to occur and enabling vehicle starting.
The keyless entry system has the following components:
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Keyless entry transmitter
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Rear compartment antenna
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Body Control Module (BCM)
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Keyless entry control module
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Immobilizer antenna coil assembly
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Remote control door lock receiver
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Keyless Entry Transmitter
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The keyless entry transmitters are used to lock and unlock the vehicle door while away from the immediate are of the vehicle. Vehicles without remote start will operate at a distance of up to 20 m (65 ft) away. Vehicles with remote start will operate at a distance of up to 60 m (195 ft) away.
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Front Console Passive (Instrument Panel) Antenna
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This antenna is located in the lower instrument panel near the front of the center console.
The front console antenna is used for vehicle starting functions. When the ignition mode switch is pressed, the antenna is energized or "pinged". A low frequency call signal is transmitted and is received by the keyless remote control transmitter. The transmitter will then reply to this challenge with a response and, if correct, vehicle starting will occur.
This antenna is located in the rear of the center console.
The rear console antenna is used for vehicle starting functions. When the ignition mode switch is pressed, the antenna is energized or "pinged". A low frequency call signal is transmitted and is received by the keyless remote control transmitter. The transmitter will then reply to this challenge with a response and, if correct, vehicle starting will occur.
This antenna is located in the center of the rear compartment metal floor pan, near the seatback.
The rear compartment antenna is used for vehicle starting functions. When the ignition mode switch is pressed, the antenna is energized or "pinged". A low frequency call signal is transmitted and is received by the keyless remote control transmitter. The transmitter will then reply to this challenge with a response and, if correct, vehicle starting will occur.
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Remote Control Door Lock Receiver
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The remote control door lock receiver is located on the vehicle windshield, directly in front of the inside rearview mirror.
The remote control door lock receiver is control by and directly communicates with the body control module (BCM). When the transmitter receives a low frequency call from an antenna it replies with an RF message. This RF message is received by the remote control door lock receiver and communicated to the BCM. If the RF message is a valid response to the low frequency challenge, vehicle starting will be allowed.
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Immobilizer antenna coil assembly
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The keyless entry immobilizer coil assembly is located in the center console, directly beneath the transmitter pocket. If the transmitter battery is dead, weak, or the RF signal is being interrupted, the transmitter may be placed in the pocket to create a low powered coupling between the transmitter and immobilizer antenna, allowing communications to occur and enabling vehicle starting.
The immobilizer antenna coil is controlled by the BCM. The immobilizer control module is also active when learning transmitters.
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Keyless Entry Control Module
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The keyless entry control module is a multi-function module which performs the following keyless entry system functions:
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Activating vehicle antennas for keyless start functions
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Backup control for the ECM accessory wakeup and the run/crank relay
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Redundant power moding, in addition to the BCM
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Ignition mode switch monitoring
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Body Control Module (BCM)
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The BCM is a multi-function module that performs the following functions:
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Receive and authenticate active transmitter and keyless start signals from the remote control door lock receiver
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Determines the functionality requested by the transmitter signal
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Performs the function requested by the transmitter signal
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Momentarily press the transmitter UNLOCK button in order to perform the following functions:
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Unlock only the driver door
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Illuminate the interior lamps for a determined length of time, or until the ignition is turned ON
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Flash the exterior lights, if enabled through personalization
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Disarm the content theft deterrent system
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Deactivate the content theft deterrent system when in the alarm mode
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Unlock All Doors - Second Operation
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Momentarily press the transmitter UNLOCK button a second time, within 5 seconds of the first press, to perform the following function:
Unlock the remaining doors and liftgate
Press the transmitter LOCK button to perform the following functions:
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Lock all vehicle doors and the liftgate
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Immediately turn off the interior lamps
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Flash the exterior lights, if enabled through personalization
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Chirp the horn, if enabled through personalization
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Arm the content theft deterrent system
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Power Liftgate, if equipped
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Press and hold the power liftgate button to perform the following functions:
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Open or close the liftgate using the power liftgate function
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Sound the interior power liftgate chime
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Vehicle Locator/Panic Alarm/Active
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A single press of the panic button performs the following functions. Some functions may be dependent on personalization settings:
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Pulses the horn three times
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Flashes the exterior lamps three times
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A press and hold of the panic button performs the following functions:
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A press and hold of the panic button performs the following functions:
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Pulses the horn and flashes the parking lamps for 30 second or until the following conditions occur:
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The panic button is pressed
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The ignition mode is turned to the RUN position with a valid keyless entry transmitter
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Remote Vehicle Start/Active
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The remote vehicle start function allows engine starting while not in the vehicle. It also allows the vehicle HVAC system and other vehicle systems to enable, providing a comfortable vehicle upon entry. Remote vehicle start functions have an operating range of up to 195 feet, depending on conditions. The remote vehicle start sequence begins by pressing and releasing the lock button and then pressing and holding the remote vehicle start buttons on the keyless entry transmitter. The turn signal lamps will illuminate to indicate the vehicle has received the remote start request. Each time a remote vehicle start is performed, the vehicle doors are locked, however they may then be unlocked/locked with the transmitte at any time. Once activated, the engine is allowed to run for 10 minutes. The remote vehicle start time may be extended by an additional 10 minute by again pressing and releasing the lock button and then pressing and holding the remote vehicle start buttons on the transmitter. This feature is called a remote vehicle start continue and allows a maximum of 20 minutes of engine running. If the remote vehicle start continue is performed at 7 minutes into the initial 10 minute time-out, a total of 17 minutes of engine running would occur. The remote vehicle start event may be suspended at any time by pressing only the remote vehicle start button on the transmitter or by entering the vehicle and turning ON the hazard lamps.
In between ignition cycles, only two remote vehicle start events may occur or be attempted. Once two events or attempts have been made, future remote vehicle start events will be suspended until the vehicle is started using the ignition.
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Enable/Disable Remote Vehicle Start/Active
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Using the driver information center, remote vehicle start may be enabled or disabled as a part of vehicle personalization. Refer to the vehicle owners manual for more information.
The hood switch provides status of the hood to the BCM for remote vehicle start purposes. The switch is integrated into the hood latch assembly. The hood ajar switch provides 2 separate inputs to the BCM. These separate inputs allow the BCM to actively monitor for a hood ajar switch fault.
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Remote Vehicle Start Circuit Description/Active
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The BCM receives a signal from the keyless entry transmitter indicating a remote vehicle start request. The BCM uses the following inputs to confirm that the system is ready to perform a remotely controlled start.
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Vehicle is not in valet mode
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All vehicle doors are closed
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Rear compartment lid is not ajar
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The hazard switch is OFF
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Battery reconnect has not occurred
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Vehicle power mode is correct.
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When the BCM determines all conditions meet those required for an remote vehicle start event, a message is sent via serial data to the ECM. The ECM relies on the remote vehicle start message from the BCM to enable remote vehicle start when the crank request signal is received. If the ECM does not receive a valid remote vehicle start message, it will not ground the control circuit of the crank relay and start the engine. While the ECM is in remote vehicle start mode it will cut fuel to the engine if any of the following additional conditions occur:
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Vehicle speed is greater than 0.
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Transmission is not in P.
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Excessive engine coolant temperature
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The malfunction indicator lamp (MIL) is commanded ON.
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Engine crank time is greater than 30 seconds.
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Excessive engine speed.
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Accelerator pedal position too high.
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Remote start timer equals 0.
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Immobilizer system indicates a theft attempt
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Keyless Entry Personalization
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Vehicle lock/unlock functions and remote vehicle start settings may be personalized for the vehicle. For functional descriptions and programming instructions, refer to the vehicle owners manual.
