Kia Forte: Description - Smart Key System - Body Electrical System - Kia Forte TD 2014-2019 Service ManualKia Forte: Description

Second generation YD (2014-2019) / Kia Forte TD 2014-2019 Service Manual / Body Electrical System / Smart Key System / Description

The SMART KEY system is a system that allows the user to access and operate a vehicle in a very convenient way. To access the vehicle, no traditional key or remote control unit is needed.
The user carries a SMART KEY FOB which does not require any conscious actions by the user (e.g. operate a RKE button). The SMART KEY system is triggered by pressing a push button in the door handle.
After being triggered the vehicle sends out a request in a limited range. If the SMART KEY FOB receives this request, it automatically sends a response to the vehicle. Then the system decides whether to perform a particular action (unlocking, locking) or remain inactive.
Again, a communication between the vehicle and the SMART KEY FOB is needed before any actions will be performed.
The System offers the following features :
Passive unlock via door driver side and passenger side
Passive locking via door driver side and passenger side
Passive start
Passive access trunk via the trunk lid switch at the trunk
Passive locking via tailgate
Max. 2 fobs can be handled by the system
Immobilizer backup antenna integrated into SSB for TP authentication (i.e. limp home mode)
Communication with engine management system
LF-RF communication
Passive unlock
The system allows the user to access (unlock) the vehicle without performing any actions with the SMART KEY FOB. This feature could be different depending on platform as follows:
Pressing Push button in door handle
Passive locking
The system allows the user to lock the vehicle by pushing a button on door handle with the SMART KEY FOB.
Button start
The system allows to switch the power modes (Off, Accessory, Ignition), as well as to start and stop the vehicles engine without performing any actions with the SMART KEY FOB. See Button Engine Start system specification.
Additionally, the system offers so called limp home mode, which is the user can operate all vehicle functions by pushing the key into the SSB.
Smart Key ECU (SMK ECU)
The SMK ECU manages all functions related to Passive Unlock, Passive Lock and Passive Authorization for Engine Start Operation.
It reads the inputs (Push button in door handle, Start Stop Button (SSB), PARK position Switch), controls the outputs (e.g. exterior and interior antennas), and communicates via the CAN (depends on the vehicle) as well as a single line interface to further devices of the car.
For communication with the SMART KEY FOB, SMK ECU generates a request (challenge) as an encoded and modulated 134.2 kHz signal at the inductive antenna outputs and receives the SMART KEY FOBs response via the external RF receiver.
The main functional blocks of the SMK ECU are:
Power supply
Microcontroller with FLASH Memory
Single Line Interface to EMS
Input stage
LF antenna amplifier/driver
CAN communication with BCM
The LF antenna amplifier/driver generates a 134.2 kHz sinusoidal carrier signal which is distributed to the different antennas.
Smart Key FOB
The system supports up to 2 SMART KEY FOBs.
The main functions of the SMART KEY FOB are:
Passive functionality: receives LF-challenge and sends automatically RF response.
Classic RKE function by action up to 3 push buttons.
Transponder-functionality in case of a flat battery or a disturbed communication.
LED for operation feedback and battery monitoring.
The FOB's LED indicator may continue to light even with a low transmitter battery.
If the performance or range of the FOB is less than expected, check the transmitter battery.
Emitting LF Antennas:
Inductive antennas in and at the vehicle are used to transform the current, driven by the SMK ECU antenna driver, into a 134.2 kHz magnetic field, which is the carrier for the SMART KEY challenge.
Three antennas cover the vehicles exterior: two antennas in the Door Handles (DS and PS) cover the area around the doors; one antenna in the rear bumper covers the area around the trunk.
Up to two antennas cover the vehicles interior and the trunk interior: one in the passenger compartment and one in the trunk.
Bidirectional Immobilizer Antenna (for Limp Home):
The Immobilizer Backup Antenna is used for sending and receiving data: it emits a magnetic field (134.2 kHz challenge) and receives changes in the field strength (response of Transponder).
Door Handle
The front door handles of the two doors (driver door / passenger door) are equipped with emitting LF-antennas to emit the 134.2 kHz signals. The front door handles are also equipped with a push button.
Push Button
The push button in door handle serves as a trigger to indicate the users intent to unlock or lock the vehicle.
The push buttons are installed at front doors, integrated into the door handles.
Another button is installed at the trunk lid.
Component Location
Component Location (1) 1. Smart key unit 2. External buzzer 3. Door outside handle 4. Interior antenna 5. RF receiver Component Location (2) 1. Bump ...

Passive Functions The system allows the user to access the vehicle without having to perform any actions (e.g. RKE button pressing) with the SMART KEY FOB. It is sufficient that a valid S ...

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