Description and Operation

Description

The SMART KEY system allows the user to access and operate the vehicle in a very convenient way. To access the vehicle, no traditional key or remote control is required. The user carries the SMART KEY fob, which does not require any conscious action by the user (such as pressing the RKE button). The SMART KEY system is triggered by pressing the button on the door handle. After activation, 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 the specific function (unlock, lock...) or remain inactive. Again, communication between the vehicle and the SMART KEY FOB is required before any actions can be performed. The system offers the following features:

• Passive Unlock via 4 Doors
• Passive Lock via 4 Doors
• Passive Start
• Passive Trunk Access via Trunk Lid Switch
• A maximum of 2 fobs can be processed by the system
• Immobilizer backup antenna driver is integrated into the SSB for TP authentication (i.e. keyless home 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.
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
   Start Button. The system allows the user to switch power modes (OFF, ACC, IGN), as well as start and stop the vehicle engine, without performing any actions with the SMART KEY fob. Refer to Engine Start/Stop 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 inserting the key into the ignition key slot (ISK).

The Smart Key ECU (SMK ECU) controls all functions related to Passive Unlock, Passive Lock and Passive Engine Start Enable. It reads inputs (door handle button, Start-Stop button (SSB), PARK position switch), controls outputs (e.g. external and internal antennas), and communicates via CAN as well as a single-wire interface with other devices in the vehicle. To communicate with the SMART KEY FOB, the SMK ECU generates a challenge in the form of an encoded and modulated 125 kHz signal on the outputs of the LF induction antennas and receives the response from the SMART KEY FOB 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 carrier signal at 125 kHz, which is distributed to the various antennas. Smart Key FOB 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 inside and outside the vehicle are used to convert the current controlled by the SMK LF antenna driver into a magnetic field at a frequency of 125 (or 134.2) kHz. This field is the carrier for the SMART KEY call. Three antennas cover the exterior of the vehicle: 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 luggage compartment or rear door. Up to three antennas cover the vehicle interior and the luggage compartment or rear door interior: two in the passenger compartment and one in the rear door room or luggage compartment.
2. 2
   Bidirectional Immobilizer Antenna (for Limp Home): The backup immobilizer antenna is used to send and receive data: it emits a magnetic field (125 - 135 kHz call) and receives changes in field strength (transponder response).
3. 3
   Receiver. The SMART KEY fob response is received through the RF receiver.

Door handle The front door handles of both doors (driver/passenger) are equipped with LF transmitting antennas to emit 125 kHz signals. The front door handles are also equipped with a button. Pressing the button on the door handle serves as a trigger to indicate the user's intention to unlock or lock the vehicle. The buttons are installed on the front doors, integrated 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 actions (e.g. pressing the RKE button) with the SMART KEY FOB. It is sufficient that a valid SMART KEY FOB is within a specified and limited range with respect to the vehicle. Thus, the system is able to detect and authenticate the SMART KEY FOB within the ranges specified below.

Operating Range

The SMART KEY FOB receives and interprets the challenge sent by the vehicle via the external antennas in free space within a minimum radius of 0.7 m, measured around the external antennas integrated into the door handles; refer to the illustration below. The access range for the trunk or tailgate is also a minimum of 0.7 m, measured from the antenna location. The SMART KEY FOB receives and interprets the challenge sent by the vehicle via the external antennas in free space within a minimum radius of 0.7 m, measured around the external antennas integrated into the door handles; refer to the illustration below. Passive entry (Passive unlock) Pressing the door handle button when all doors are locked indicates that the operator intends to access the vehicle and thus starts the system to unlock. Passive lock Pressing one of the door handle buttons 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 and one of the buttons, except the front left side, operate.

indicates the operator's intention to lock the vehicle and thus triggers the system to lock. Passive trunk reminder (sedan only) Whenever the trunk is closed, the SMK ECU uses a suitable search strategy to avoid the trunk buzzer warning that the FOB is outside the vehicle. The SMK then searches for a SMART KEY FOB inside the trunk compartment. If a valid SMART KEY FOB is found in the trunk, the SMK ECU activates the external SMK buzzer (to be confirmed) to inform the user that the trunk is closed with the FOB inside the trunk. The SMK will send a trunk open command to the BCM to reopen the trunk if the trunk reopen bit (BK) is set. For this function, a 'valid' SMART KEY FOB means any SMART KEY FOB belonging to the vehicle, even if it is DEACTIVATED.Smart trunk When a user with a valid Smart Key stands near the rear bumper (within the LF antenna range) for more than 3 seconds, the trunk opens.

1. 1
   The rear bumper antenna detects a valid SMART KEY nearby.
2. 2
   When a valid SMART KEY enters the rear bumper antenna zone, the buzzer sounds and the hazard lamp flashes once to confirm detection.
3. 3
   If the electronic key remains within the rear bumper detection range (antenna range) for more than 3 seconds, the buzzer and hazard lamp sound twice and the luggage compartment opens.
4. 4
   Preconditions: All terminals OFF, at least one door open, lock status not locked. Checked by SMK every 100 ms while CAN/LIN is active.
5. 5
   Event: Status of at least 1 door handle changed from unlocked to locked.
6. 6
   SMK Actions:

   • IF the fob is not active, the SMK searches for fobs inside the vehicle. The same LF strategy must be used as for the No ID 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 number reminder. If any valid fob is found, the SMK unlocks the vehicle by sending a CAN/LIN key unlock reminder message with the fob number.
7. 7
   Preconditions: All terminals OFF and any door (including the luggage compartment) open, and no FOB-IN and no lock status (checked by SMK periodically every 100 ms while CAN/LIN is active).
8. 8
   Vehicle action: Closing the last door or luggage compartment while the handle lock state is locked or while in progress.
9. 9
   SMK actions: After 500 ms from closing, if all doors are locked, then:

   • IF the fob is not active, the SMK searches for fobs inside the vehicle. The same LF strategy must be used as for the No ID 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 an unlock command over CAN and activates the additional buzzer warning. If any valid fob is found, the SMK sends an unlock command over CAN/LIN and activates the additional buzzer warning.
10. 10
    If the terminal status is ACC or IGN, all doors are closed, and this user triggers SMK lock, a search begins outside the vehicle from the trigger side.
11. 11
    If a valid fob is not found, no action is required, but if a valid fob is found, the buzzer warning must be activated.
12. 12
    If "b_Trunk Option == On" and "b_Trunk Lock Unlock Option == On" are both met, the lock warning includes the rear door as a door and the rear door unlock handle as the door unlock switch.
13. 13
    If the terminal status is OFF and not all doors are closed, and this user triggers SMK lock, a search begins outside the vehicle from the trigger side.
14. 14
    If a valid fob is not found, no action is required, but if a valid fob is found, the buzzer warning must be activated.
15. 15
    If "b_Trunk Option == On" and "b_Trunk Lock Unlock Option == On" are both met, the lock warning includes the rear door as a door and the rear door unlock handle as the door unlock switch.
16. 16
    If the terminal status is OFF, ATWS is considered disarmed, all doors are closed, and this user activates SMK lock, a search begins inside the vehicle;
17. 17
    if a valid fob is not found, the SMK lock search is started, but if a valid fob is found, an audible warning must be activated.
18. 18
    If "b_Trunk Option == On" and "b_Trunk Lock Unlock Option == On" are both met, the lock warning includes the rear door as a door and the rear door unlock handle as the door unlock switch.
19. 19
    If the final state is ACC or IGN and vehicle speed is less than 3 km/h, a periodic search (every 3 seconds) is performed inside the vehicle to confirm that a valid fob is still in the vehicle.
20. 20
    If a valid fob is not found, a warning is triggered, but if a valid fob is found, no action is triggered.

Smart Key reminder 1 Smart Key reminder 2 Smart Key door lock warning Door lock warning 1 Door lock warning 2 Door lock warning 3 Smartkey indicator warning Fail-safe functions (backup for limp home) In case of SMART KEY FOB battery discharge or transmission failure, the following functions are available:

• Locking/unlocking doors or luggage compartment (or rear door depending on vehicle configuration): using the 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 over CAN (external buzzer warning and internal buzzer).
   • If a door is opened and closed during ignition on and 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.

FOB low battery voltage detection For detection of a low battery condition of the FOB, a battery voltage measurement and low-voltage detection strategy is implemented in the FOB. The battery voltage will be measured when the FOB button is pressed or when an LF command is received. Learning description This section describes the learning procedure for the SMK and FOB. To learn the SMK and FOB, a connection to the diagnostic tool is required. Learning mode In any mode, the learning process is controlled by the SMK. Before starting the learning service, the Fob-In signal must be active and the vehicle secret code (called the PIN code) must be known. Learning mode This mode is used by dealers to replace the SMK and/or key set, or to register additional keys for an existing system. This means the system has already been learned with a specific PIN code. The PIN code is fixed for the life of the vehicle, so the same PIN code must be used in this mode. Otherwise, learning will fail. Description of learning mode procedure (step by step) Purpose: Key learning procedure at the service station Initial condition:

• SMK replacement: SMK is not registered, while the SMART FOB is already registered with the same PIN code.
• Registering additional or new keys: SMKs are already registered with the same PIN code.

Start after replacement (initial start) Starting is possible in the following order after replacing the new Smart Key ECU or SMART KEY 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.