Kia Sorento: Description

Second Generation XM (2011-2024) / Kia Sorento XM 2011-2024 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 driver integrated into SSB for TP authentication (i.e. limp home mode)

•	Communication with engine management system

•	Communication with SRX

•	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:

A.	Pressing Push button in door handle

2.	Passive locking The system allows the user to lock the vehicle by pushing a button on door handle with the SMART KEY FOB.

3.	Button start The system allows the user to switch the power modes (Off, Accessory, Ignition), as well as to start and stop the vehicle’s engine without performing any actions with the SMART KEY FOB. See Button Engine Start system specification.

4.	LIMP HOME Mode 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 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 125 (or 134.2) kHz signal at the inductive antenna outputs and receives the SMART KEY FOB’s 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 125 (or 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 4 push buttons.

•	Transponder-functionality in case of a flat battery or a disturbed communication.

Antennas

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 125 (or 134.2) kHz magnetic field, which is the carrier for the SMART KEY challenge.

Three antennas cover the vehicle’s 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 or tailgate.

Up to three antennas cover the vehicle’s interior and the trunk or tailgate interior: two in the passenger compartment and one in the tailgate room or trunk.

2.	Bidirectional Immobilizer Antenna (for Limp Home): The Immobilizer Backup Antenna is used for sending and receiving data: it emits a magnetic field (125 - 135 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 125 (or 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 user’s 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 or tailgate lid.

Component Location (2)

1. Door outside handle button 2. Door outside handle 3. Bumper antenna 4. Tailgate switch ...

Operation

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 ...

Kia Sorento: Description

Component Location (2)

Operation

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