Keyless Entry System Description and Operation (With ATH)
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Keyless Entry System Description and Operation (With ATH)
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Keyless Entry System Description and Operation - Active
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 a door, operate the power lift gate (if equipped), release the lift glass (if equipped) or open the rear compartment lid when a corresponding button on the keyless entry transmitter is pressed. This is accomplished by the transmitter sending a radio frequency to the Remote Control Door Lock Receiver antenna that has a direct link to the Body Control Module (BCM). The BCM interprets the signal and activates the requested function or request the appropriate ECU 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 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. Keyless entry allows you to operate the following features:
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Rear compartment lid release
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Illuminated entry lamps
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Panic alarm/Vehicle locator
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Automatic window express down, if equipped. Automatic window express up, if equipped
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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 several 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 the rear compartment touch pad, the low frequency antenna sends out a challenge to the keyless entry transmitter. The transmitter should 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. Passive entry allows you to operate the following features:
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Passive door unlock/unlatch and lock
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Passive rear compartment lid release
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Illuminated interior lamps
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Key In Vehicle Reminder
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Transition to off or transition from one or multiple doors open to all doors close, vehicle will sounds three horn chirps if key is left in vehicle - upon next door opening will get a DIC message and interior chime.
Lock out deterrent, in off power mode, one or multiple doors become open, press the interior courtesy lock switch, close all doors, if key fob remains in the vehicle the driver door will unlock.
The keyless entry system has the following components:
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Keyless entry integrated key/transmitter
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Driver and front Passenger door antennas (part of the door handle assembly)
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Driver and front Passenger door lock sensors (part of the door handle assembly)
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Note
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Rear doors do not have antennas.
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Trunk antenna (rear compartment)
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Body Control Module (BCM)
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Keyless Entry Control Module
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Immobilizer Coil Assembly (used to learn keys, start vehicle when key battery is dead or when RF interference is present)
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Remote Control Door Lock Receiver
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Keyless Entry Transmitters
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The keyless entry transmitters are used to passively:
Lock, unlock, release trunk, and start vehicle.
The keyless entry transmitters are used to actively:
Lock, unlock, locate vehicle via panic/locator, release trunk, and remote start vehicle.
By operating any of the exterior door handles, a nearby programmed transmitter is challenged by a keyless entry antenna. The transmitter will passively send a request to the BCM. The BCM will interpret this communication and either allow entry into the vehicle or deny it.
This is accomplished by the transmitter sending a radio frequency to the antenna that has a direct link to the body control module (BCM). The BCM interprets the signal and activates the requested function or request the appropriate ECU to activate the function via a serial data message.
The keyless entry door antennas are used to transmit low frequency communications to the keyless entry transmitters.
The keyless entry door antennas are molded into the vehicles left front and right front exterior door handles. The antennas are serviced as part of the door handle assembly. The antennas are controlled by the Keyless Entry Control Module. When the exterior door handle is operated, the respective antennas sends out a challenge to the keyless entry transmitter which begins the passive entry communications.
The rear fascia antenna is used to transmit low frequency communication to the keyless entry transmitters for entry to rear compartment.
The rear fascia antenna is located under the rear fascia and is accessed from under the vehicle. The antenna is controlled by the Keyless Entry Control Module. When the rear compartment touch pad is pressed, the antenna sends out a challenge to the keyless entry transmitter which begins the passive entry communications.
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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 very front end of console.
The keyless entry front console (instrument panel) antenna is used for both keyless entry and vehicle starting functions. For both functions, it is used to locate any keyless entry transmitters within the vehicle.
This antenna is located in the rear end of the console.
The keyless entry rear console antenna is used for both keyless entry and vehicle starting functions. For keyless entry functions, it is used to locate any keyless entry transmitters within the vehicle.
For the keyless start function, when the "start/stop" button is pressed, this antenna sends out a challenge to the keyless entry transmitter which begins the passive start communications.
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Trunk antenna (rear compartment)
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This antenna is located in the trunk in the center of the metal floor pan near the seatback.
The keyless entry trunk antenna is used for both keyless entry and vehicle starting functions. For both functions, it is used to locate any keyless entry transmitters within the vehicle.
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Immobilizer Coil Assembly
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The keyless entry immobilizer coil assembly is located in the center console. It has a small pocket above where the key fob can be inserted if the key fobs battery is dead, weak, or the radio frequency signal is being interrupted.
The purpose of the immobilizer coil is to send a low frequency radio frequency challenge to a learned key when the start button is pressed. The immobilizer coil is controlled by the Body Control Module.
The other function of the immobilizer coil is for learning the keys to the vehicle.
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Keyless Entry Control Module (PEPS)
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The Keyless Entry Control Module (PEPS) is a multi-function module which performs the following passive keyless entry functions:
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Transmitting vehicle antennas for passive keyless entry functions
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Backup control for the ECM accessory wakeup and the run/crank relay
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If equipped, acts as the low side driver for the electronic steering column lock
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Receiver of the door handle switch inputs and the lock sensor inputs and door open switch (not the door ajar switch)
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Driver for the unlatch motors - happens when the BCM unlatch enable signal is active and when the appropriate door handle is pulled
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Start/stop button/switch is an input to the PEPS
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Body Control Module (BCM)
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The Body Control Module (BCM) is a multi-function module that performs the following functions:
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Receive active and passive signals from fobs
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Authenticates the active and passive signals from the integrated key/transmitter
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Determines the functionality requested by the fob signal
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Performs the function requested by the fob signal
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Unlock Driver Door Only - Active
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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 enable through personalization
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Disarm the Content Theft Deterrent (CTD) system
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Deactivate the CTD system when in the alarm mode
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Unlock All Doors - Second Operation - Active
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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
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Unlock Driver Door Only - Passive
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If enabled through personalization, approach the driver door with a valid keyless entry transmitter and pull the door handle to perform the following functions:
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Unlock and open only the driver door when door handle is operated
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Disarm the CTD system, if equipped
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Deactivate the CTD system when in the alarm mode
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Unlock All Doors - Passive
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Approach any non driver door (front or rear) or if enabled through personalization, driver door with a valid keyless entry transmitter to perform the following functions:
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Unlock all vehicle doors when the approached door handle is operated
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Only opens door whose door handle is pulled
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Disarm the CTD system, if equipped
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Deactivate the CTD system when in the alarm mode
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Press the transmitter LOCK button to perform the following functions:
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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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Exit the vehicle (with ignition off) with the keyless entry transmitter to automatically perform the following functions, if equipped.
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Lock all vehicle doors after a delay
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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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When all doors are closed, they can also be locked from the exterior by touching the lock sensor on the outside of a front door handle while having a valid transmitter in range. This function is only active for several minutes after all doors are closed to save battery life.
If more than one keyless entry transmitter is within a vehicle and the Keyless Entry System detects that one or more transmitters have been left in the vehicle after vehicle is locked, any transmitter left within the vehicle will be temporarily deactivated until:
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A button on the deactivated key fob is pressed (will only activate the fob whose button is pressed)
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A passive unlock of vehicle occurs
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Change in power mode occurs
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Rear Compartment Lid Release - Active
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If the vehicle transaxle is in PARK or NEUTRAL and the ignition is in the OFF position, a single press of the transmitter rear compartment release button will open the rear compartment lid.
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Rear Compartment Lid Release - Passive
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Approach the rear of the vehicle with a valid keyless entry transmitter. Press the rear compartment lid release touch pad. The rear compartment lid will open.
If vehicle is not equipped with trunk antenna, a keyless entry transmitter left inside the truck will allow the trunk to be reopened at any time. This feature will not allow a customer to lock the transmitter in the trunk.
If vehicle has a trunk antenna and one or more transmitters are left in the trunk or interior of the vehicle, those transmitter(s) will be deactivated when the vehicle becomes locked.
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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 switch is turned to the RUN position with a valid key
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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 59 m(195 feet), depending on conditions. The remote vehicle start sequence begins by pressing and releasing the lock button and then within 3 seconds, pressing and holding the remote vehicle start buttons on the keyless entry transmitter. The turn signal lamps will flash 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 transmitter or vehicle key 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 that informs that there is a remote start request. The BCM uses the following inputs to confirm that the system is ready to remotely start the car.
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The transmitter is not in the vehicle.
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Coolant temperature is not too high.
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Two remote vehicle start periods has not been used.
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No emission control system malfunktion.
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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.
A LOW FOB BATTERY message may be seen on the driver information center when the fob"s battery voltage has been lower than 2.16 volts for three consecutive ignition cycles (OFF to ACC or OFF to RUN). The BCM module monitors the voltage of each individual key fob. If two keys are in the vehicle when it is started, only the voltage of the key used to start the vehicle is monitored. For example, if Fob 1 enters from the driver door and Fob 2 enters from the passenger door, the Body Control Module will monitor only Fob 1. To determine the fob being monitored, check which driver ID is present when the vehicle is started. The driver ID will correspond with the fob being monitored.
