Description and Operation

Description

The SMART KEY system allows the user to access and operate the vehicle in a very convenient way. No traditional key or remote control is required to access the vehicle. The user carries the SMART KEY FOB, which does not require any conscious action by the user (such as pressing an RKE button). SMART KEY The system is activated by pressing the button on the door handle. Once activated, the vehicle sends a request within a limited range. If the SMART KEY FOB receives this request, it automatically sends a response to the vehicle. The system then decides whether to perform a certain action (unlock, lock...) or remain inactive. Again, communication between the vehicle and the SMART KEY FOB is required before any action is performed. The system provides the following functions:

• Passive Unlock via Driver and Passenger Door
• Passive Lock via Driver and Passenger Door
• Passive Start
• Tailgate Passive Entry via Tailgate Open Switch on Tailgate
• Passive Lock via Tailgate
• A maximum of 2 fobs can be processed by the system
• Immobilizer backup antenna driver is integrated in the SSB for TP authentication (i.e., in idle mode)
• Communication with Engine Management System
• Communication with SRX
• LF-RF Communication

1. 1
   Passive Unlock. The system allows the user to access (unlock) the vehicle without performing any action with the SMART KEY fob. This feature may differ depending on the platform as follows:

   • Pressing the Button on the Door Handle
2. 2
   Passive Lock. The system allows the user to lock the vehicle by pressing the button on the door handle with the SMART KEY fob.
3. 3
   Engine Start Button. The system allows switching of power modes (OFF, ACC, ON), and starting and stopping the vehicle engine without performing any operation with the SMART KEY fob. Refer to Engine Start Button system specification.
4. 4
   LIMP HOME Mode. In addition, the system provides a so-called "limp home" mode, in which the user can operate all vehicle functions by pressing the key against the SSB.

Smart Key Control Unit (SMK ECU) The SMK ECU controls all functions related to Passive Unlock, Passive Lock, and Passive Engine Start Authorization. It reads inputs (door handle button, Start Stop Button (SSB), PARK position switch), controls outputs (such as external and internal antennas), and communicates via CAN as well as a single-wire interface with other vehicle devices. To communicate with the SMART KEY FOB, the SMK ECU generates a request (challenge) in the form of an encoded and modulated 125 kHz signal, which is output by the inductive antenna, and receives the SMART KEY FOB response via an external RF receiver. The main functional blocks of the SMK ECU are:

• Power Supply
• Flash Memory Microcontroller
• Single-Wire Interface to SRX
• Single-Wire Interface to EMS
• Input Stage
• LF Antenna Amplifier/Driver
• CAN Communication with BCM

LF Antenna Amplifier/Driver generates a sinusoidal 125 kHz carrier signal, which is distributed to the different antennas. SMART KEY FOB The system supports up to 2 SMART KEY FOBs. Main functions of the SMART KEY FOB:

• Passive Function: receives the LF call and automatically sends an RF response.
• Classic RKE function by means of up to 4 buttons.
• Transponder operation in case of battery discharge or communication failure.

Antennas

1. 1
   LF Transmitting Antennas: Inductive antennas in and on the vehicle are used to convert the current supplied by the SMK ECU antenna driver into a 125 kHz magnetic field, which is the carrier for the SMART KEY call. Three antennas cover the exterior of the vehicle: two antennas in the door handles (DR and PS) cover the area around the doors; one antenna in the rear bumper covers the area around the luggage compartment or tailgate. Up to three antennas cover the vehicle interior and the luggage compartment or tailgate interior: two in the cabin and one in the luggage compartment or trunk.
2. 2
   Bidirectional Immobilizer Antenna (for Limp Home): The backup immobilizer antenna is used to send and receive data: it radiates a magnetic field (125 - 135 kHz call) and receives changes in field strength (transponder response).
3. 3
   External Receiver. The SMART KEY FOB response is received through an external RF receiver, which is connected to the SMK ECU via a serial communication line. The SMK ECU has a connector pin for the serial communication line.

Door handle The front door handles of both doors (driver/passenger door) are equipped with LF transmitting antennas to emit 125 kHz signals. The front door handles are also equipped with push buttons. Pressing the button on the door handle serves as a trigger indicating the user's intention to unlock or lock the vehicle. The buttons are installed on the front doors, built into the door handles. Another button is installed on the trunk lid or tailgate.

Operation

Passive Functions The system allows the user to access the vehicle without performing any action (such as pressing an RKE button) using the SMART KEY FOB. It is sufficient for a valid SMART KEY FOB to be within a specified and limited range relative to the vehicle. Thus, the system is capable of detecting and authenticating the SMART KEY FOB within the ranges shown below.

Operating Range

The SMART KEY FOB receives and interprets the call sent from the vehicle through the exterior antennas in free space within a minimum radius of 0.7 m around the exterior antennas built into the door handle; refer to the illustration below. Trunk or tailgate access range is also minimum 0.7 m from the antenna location. The SMART KEY FOB receives and interprets the call sent from the vehicle through the exterior antennas in free space within a minimum radius of 0.7 m around the exterior antennas built into the door handle; refer to the illustration below. Passive Entry (Passive Unlock) Pressing one of the buttons on the door handles when all doors are locked indicates the operator's intention to access the vehicle and thus activates the system to unlock. Passive Lock (Exit) Pressing one of the buttons on the door handles when one of the following conditions is met:

• At least one door is open and the two-step timer is not running, or
• The two-step timer is running and one of the buttons other than the front left one is activated.

indicates the operator's intention to lock the vehicle and thus activates the locking system. Passive Trunk Open Pressing the trunk/tailgate switch when the trunk/tailgate is closed indicates the operator's intention to open the trunk/tailgate and thus starts the system. The SMK ECU then sends an LF challenge to the SMART KEY FOB through the bumper external antenna. The SMART KEY FOB responds with an RF response. If the received response matches the expected response, the SMK ECU sends a "Trunk/Tailgate Open" message over the CAN network. Smart Key Reminder 1

1. 1
   Preconditions: All terminals OFF, at least one door open, and lock status not locked. Checked by the SMK periodically every 100 ms while CAN/LIN is active.
2. 2
   Event: Status of at least 1 door handle changed from unlocked to locked.
3. 3
   SMK Actions:

   • IF the FOB is not active, the SMK searches for FOBs inside the vehicle cabin. Use the same LF strategy as for the ID OUT warning (registration only, no authentication).
   • IF the FOB is ACTIVE, the SMK searches for a valid TP.

   If no FOB or TP is found, no action is required. If any valid FOB or valid TP is detected, the SMK unlocks the vehicle by sending a CAN key unlock message with the FOB count. If any valid FOB is detected, the SMK unlocks the vehicle by sending a CAN/LIN key reminder unlock message with the FOB number.
4. 4
   Preconditions: All terminals OFF, any door (including trunk) open, and no FOB-IN and lock status (periodically checked by the SMK every 100 ms while CAN/LIN is active).
5. 5
   Vehicle action: Closing the last door or trunk with the handles locked or while locking is in progress.
6. 6
   SMK actions: 500 ms after closing, if all doors are locked, then:

   • IF the FOB is not active, the SMK searches for FOBs inside the vehicle cabin. Use the same LF strategy as for the ID OUT warning (registration only, no authentication).
   • IF the FOB is ACTIVE, the SMK searches for a valid TP.

   If no FOB is found, no action is required. If any valid FOB or valid TP is found, the SMK sends a CAN unlock command and activates the additional buzzer warning. If a valid FOB is found, the SMK sends a CAN/LIN unlock command and activates the additional buzzer warning.
7. 7
   If the final state is ACC or IGN, all doors are closed, and the user initiates SMK locking, the search starts outside the vehicle from the trigger side.
8. 8
   If no valid FOB is found, no action is required, but if a valid FOB is found, the buzzer warning must be activated.
9. 9
   If performed, with the Tailgate option enabled and the Tailgate lock/unlock option enabled, the lock warning treats the tailgate as a door, and the tailgate lock release handle as the door unlock switch.
10. 10
    If the terminal state is OFF and not all doors are closed, and the user initiates SMK locking, the search starts outside the vehicle from the trigger side.
11. 11
    If no valid FOB is found, no action is required, but if a valid FOB is found, the buzzer warning must be activated.
12. 12
    If "b_TailgateOption == On" and "b_Tailgate Lock Unlock Option == On", the lock warning includes the tailgate as a door and the tailgate lock unlock handle as the door unlock switch.
13. 13
    If the terminal state is OFF, ATWS is considered disarmed, all doors are closed, and the user activates SMK locking, the search starts inside the vehicle cabin.
14. 14
    If a valid FOB is not found, the SMK locking search is started, but if a valid FOB is found, the buzzer warning must sound.
15. 15
    If "b_TailgateOption == On" and "b_Tailgate Lock Unlock Option == On", the lock warning includes the tailgate as a door and the tailgate lock unlock handle as the door unlock switch.
16. 16
    If the final state is ACC or IGN and vehicle speed is less than 3 km/h, a periodic search (every 3 s) is performed inside the vehicle to confirm that a valid FOB is still in the vehicle.
17. 17
    If a valid FOB is not found, the warning is triggered, but if a valid FOB is found, no action is triggered.

SMART KEY Reminder 2 SMART KEY Door Lock Warning Door Lock Warning 1 Door Lock Warning 2 Door Lock Warning 3 Smart Key Indicator Warning Fail-Safe Functions (Limp Home Backup) If the SMART KEY FOB battery is discharged or transmission fails, the following functions are available:

• Unlocking/locking doors or trunk (or rear door depending on vehicle equipment): with mechanical key

User Information Functions

ID OUT Warning

1. 1
   Preconditions:

   • (ACC or IGN1) & (any door open or trunk open)
2. 2
   Event: Last open door closed
3. 3
   SMK action: SMK searches for the SMART KEY FOB inside the cabin.

   • If a valid SMART KEY FOB is not found, the SMK activates the external buzzer and sends an ID OUT warning via CAN (external buzzer warning and internal buzzer).
   • If a door is opened and closed again during ignition on/off while a valid FOB is inside, the SMK re-enables authentication and stops the warning. If the terminal is in ACC mode, the SMK must turn on the immobilizer lamp.

If there is an LF fault (LF overheating or LF antenna failure), the system behaves the same as when no FOB is found.

Fob Battery Low Voltage Detection. To determine the state of the fob battery, a defined battery voltage measurement and low voltage detection strategy is implemented in the fob. The battery voltage measurement will be performed when the fob button is pressed or an LF measurement command is received. Teaching Description. This section describes the teaching procedure for the SMK and FOB. Connection to the diagnostic tester is required to teach the SMK and fobs. TEACHING MODE. In any mode, the teaching process is controlled by the SMK. Before starting the teaching service, the Fob-In signal must be active and the vehicle secret code (called the PIN code) must be known. TEACHING MODE. This mode is used by dealers to replace the SMK and/or key set, or to register additional keys for the existing system. This means the system is already taught a specific PIN code. The PIN code is fixed for the entire life of the vehicle, so the same PIN code must be used in this mode. Otherwise, the teaching will fail. TEACHING MODE. Procedure Description (Step by Step). Purpose: Key teaching procedure at the service station. Initial condition:

• SMK replacement: SMK not learned, and SMART FOB already learned with the same PIN code
• Learning Additional or New Keys: SMK is already learned with the same PIN code.

Starting After Replacement (Initial Start). Starting is possible in the following sequence after replacing the new SMART KEY or fob.

• This is for starting from the virgin state
• All related parts in initial state (smart key, ECM)
• Depress the brake pedal in P or N range
• Press the start button once with the virgin smart key.