Description and Operation

Description

The SMART KEY system allows the user to access and operate the vehicle in a very convenient way. There is no need for a traditional key or remote control 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). The SMART KEY system is triggered by pressing the button on the door handle. Once triggered, 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 action (unlock, lock...) or remain inactive. Similarly, the Electronic Steering Column Lock (ESCL) is locked and released. Again, communication between the vehicle and the SMART KEY fob must be established before any action is performed. The system offers the following functions:

• Passive Unlock via Driver and Passenger Door
• Passive Lock via Driver and Passenger Door
• Passive Start
• Passive Access to Trunk/Tailgate via Trunk/Tailgate Opening Switch
• Passive Lock via Tailgate
• 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
• 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 function may vary 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
   Start Button The system allows the user to release the ESCL and switch power modes (Off, Accessory, Ignition), as well as start and stop the engine without performing any action with the SMART KEY FOB. Refer to the Engine Start Button specification.
4. 4
   LIMP HOME Mode In addition, the system provides a so-called "limp home mode", in which the user can control all vehicle functions by inserting the key into the SSB.

Smart Key Control Unit (SMK ECU) The 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 (such as the exterior and interior 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 as an encoded and modulated 125 (or 134.2) kHz signal, outputs it on the inductive antennas, 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 EMS
• Input Stage
• LF Antenna Amplifier/Driver
• CAN Communication with BCM

LF Antenna Amplifier/Driver: Generates a sinusoidal carrier signal of 125 (or 134.2) kHz, 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 current controlled by the SMK ECU antenna driver into a magnetic field at 125 (or 134.2) kHz, which is the carrier for the SMART KEY challenge. 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 trunk or tailgate. Up to three antennas cover the vehicle interior and the trunk or tailgate: two in the cabin and one in the trunk or tailgate.
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
   External Receiver The SMART KEY FOB response is received via 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) are equipped with LF transmitting antennas for transmitting 125 (or 134.2) 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. 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 the free space within a minimum radius of 0.7 m, measured around the external antennas built into the door handles; refer to the illustration below. The access range to the luggage compartment 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 the free space within a minimum radius of 0.7 m, measured around the external antennas built into the door handles; 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 therefore 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 and one of the buttons, except the front left side, operate.

indicates the operator's intention to lock the vehicle and thus activates the system for the lock. Passive Tailgate/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 activates the system. The SMK ECU then sends an LF challenge to the SMART KEY FOB via the exterior bumper 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. Passive Trunk/Tailgate Reminder (Sedan Only) Whenever the trunk/tailgate is closed, the SMK ECU uses an appropriate search strategy to avoid a trunk/tailgate reminder buzzer when the SMART KEY FOB is outside the vehicle. The SMK then searches for the SMART KEY FOB inside the trunk/tailgate. If a valid SMART KEY FOB is in the trunk/tailgate, the SMK ECU activates the exterior SMK buzzer (to be confirmed), informing the user that the trunk/tailgate is closed with the key inside the trunk/tailgate. The SMK sends a trunk/tailgate open command to the BCM to reopen the trunk/tailgate if the trunk/tailgate 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 KEY Reminder 1

1. 1
   Preconditions: All terminals OFF, at least one door open, lock status not locked. Checked by SMK 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. 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 key fob or TP is found, no action is required. If any valid key fob or valid TP is detected, the SMK unlocks the vehicle by sending a CAN key unlock reminder message with the key fob number. If any valid key fob is found, the SMK unlocks the vehicle by sending a CAN/LIN key reminder unlock message with the key fob number.
4. 4
   Preconditions: All terminals are OFF, any door (including tailgate) is open, no FOB-IN, and no lock (checked by the SMK periodically every 100 ms while CAN/LIN is active).
5. 5
   Vehicle action: Closing of the last door or tailgate/liftgate with the handles locked or locking 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. 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.
7. 7
   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.
8. 8
   If a valid fob is not found, no action is required, but if a valid fob is found, the buzzer warning must be activated.
9. 9
   If "b_TailgateOption == On" and "b_Tailgate Lock Unlock Option == On" are met, the lock warning treats the tailgate as a door, and the tailgate unlock button as the door unlock switch.
10. 10
    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.
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_TailgateOption == On" and "b_Tailgate Lock Unlock Option == On" are met, the lock warning treats the tailgate as a door, and the tailgate unlock button as the door unlock switch.
13. 13
    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;
14. 14
    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.
15. 15
    If "b_TailgateOption == On" and "b_Tailgate Lock Unlock Option == On" are met, the lock warning treats the tailgate as a door, and the tailgate unlock button 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 seconds) 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, a 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 Smartkey Indicator Warning Fail-Safe Functions (Limp Home Backup) If the SMART KEY FOB battery is discharged or transmission fails, 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 or tailgate/liftgate 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.

Low Battery Voltage Detection of SMART KEY FOB For detection of the low battery state of the SMART KEY FOB, a defined battery voltage measurement and low voltage detection strategy is implemented in the FOB. The battery voltage is 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, ESCL and FOB. A diagnostic tool connection is required to learn the SMK, ESCL and FOB. 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 PIN code) must be known. LEARNING MODE This mode is used by dealers to replace the SMK and/or ESCL and/or key set, or to register additional keys to an existing system. This means the system is already learned to 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. LEARNING MODE Procedure Description (Step by Step) Purpose: Key learning procedure at the service station Initial condition:

• SMK Replacement: SMK is not learned, while the ESCL and SMART FOB are already learned with the same PIN code.
• ESCL Replacement: ESCL is not learned, while the SMK and SMART FOB are already learned with the same PIN code.
• Learning of additional or new keys: SMK and ESCL have already been learned with the same PIN code

Starting After Replacement (Initial Start) Starting is possible in the following order after replacing a new Smart Key unit, Key FOB or ESCL.

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