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
• Passive Trunk Access via the Trunk Switch in the Trunk
• Passive Lock via Tailgate
• A maximum of 2 fobs can be processed by the system
• Immobilizer backup antenna integrated in the SSB for TP authentication (i.e., in emergency 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 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
   Start Button: The system allows the user to release the ESCL and switch power modes (Off, Accessory, Ignition), as well as to switch the electric vehicle to READY mode and back, without any action with the SMART KEY FOB. See the Push-Button Engine Start System specifications.
4. 4
   LIMP HOME Mode: In addition, the system provides a so-called "limp home mode," with which the user can control all vehicle functions by pressing the key in the SSB.

Smart Key ECU (SMK ECU) The SMK ECU controls all functions related to "Passive Unlock", "Passive Lock" and "Passive Authorization for READY Mode" operation. It reads inputs (from the door handle button, Start Stop Button (SSB), PARK position switch), controls outputs (such as to the exterior and interior 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 encoded and modulated 125 (or 134.2) kHz signals on the inductive antenna outputs 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

The LF antenna amplifier/driver generates a 125 (or 134.2) kHz sine carrier signal, 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 with up to 4 buttons.
• Transponder operation in case of battery discharge or communication failure.
• LED for feedback and battery charge monitoring.

The FOB LED indicator may continue to illuminate even when the transmitter battery is low. If FOB performance or range is less than expected, check the transmitter battery.

Antennas

1. 1
   Transmitting LF Antennas: Inductive antennas in and on the vehicle are used to convert the current supplied 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 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. Up to two antennas cover the vehicle interior and trunk interior: one in the cabin and one in the 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 kHz trigger, 134.2 kHz) and detects changes in field strength (transponder response).

Door Handle The front door handles of both doors (driver and passenger door) are equipped with LF antennas that emit 125 (or 134.2) kHz signals. Each front door handle also has a button. 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 built into the front door handles. Another button is installed on the trunk lid or liftgate.

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 challenge sent from the vehicle via the exterior antennas in free space within a minimum radius of 0.7 m around the external antennas built into the door handles. The access range to the vehicle is also a minimum of 0.7 m from the antenna position. Passive Entry (Passive Entry): Pressing one of the buttons on the door handles while all doors are locked indicates the operator's intention to access the vehicle and thus triggers the system unlock. Passive Lock (Exit): Pressing one of the buttons on the door handles when one of the following conditions is met: indicates the operator's intention to lock the vehicle and thus triggers the system lock. Passive Trunk Open: Pressing the trunk/liftgate switch when the trunk/liftgate is closed indicates the operator's intention to open the trunk/liftgate and thus triggers the system. The SMK ECU then sends an LF challenge to the SMART KEY FOB via the exterior antenna in the bumper. The SMART KEY FOB responds with an RF response. If the received response matches the expected response, the SMK ECU sends the message "Trunk/Liftgate Open" over the CAN network. Passive Trunk Warning: Whenever the trunk is closed, the SMK ECU uses an appropriate search strategy to avoid the trunk buzzer warning with the FOB inside the vehicle. The SMK then searches for the SMART KEY FOB in the trunk. If a valid SMART KEY FOB is detected in the trunk, the SMK ECU activates the SMK exterior buzzer (TBD) to inform the user that the trunk has been closed with a FOB in the trunk. The SMK will send a trunk open command to the BCM for trunk re-opening if the trunk re-open 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.

• At least one door is open and the two-stage timer does not operate, or

The SMART KEY FOB receives and interprets the challenge sent from the vehicle via the exterior antennas in free space within a minimum radius of 0.7 m around the external antennas built into the door handles. The access range to the vehicle is also a minimum of 0.7 m from the antenna position. Passive Entry (Passive Entry): Pressing one of the buttons on the door handles while all doors are locked indicates the operator's intention to access the vehicle and thus triggers the system unlock. Passive Lock (Exit): Pressing one of the buttons on the door handles when one of the following conditions is met: indicates the operator's intention to lock the vehicle and thus triggers the system lock. Passive Trunk Open: Pressing the trunk/liftgate switch when the trunk/liftgate is closed indicates the operator's intention to open the trunk/liftgate and thus triggers the system. The SMK ECU then sends an LF challenge to the SMART KEY FOB via the exterior antenna in the bumper. The SMART KEY FOB responds with an RF response. If the received response matches the expected response, the SMK ECU sends the message "Trunk/Liftgate Open" over the CAN network. Passive Trunk Warning: Whenever the trunk is closed, the SMK ECU uses an appropriate search strategy to avoid the trunk buzzer warning with the FOB inside the vehicle. The SMK then searches for the SMART KEY FOB in the trunk. If a valid SMART KEY FOB is detected in the trunk, the SMK ECU activates the SMK exterior buzzer (TBD) to inform the user that the trunk has been closed with a FOB in the trunk. The SMK will send a trunk open command to the BCM for trunk re-opening if the trunk re-open 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.

A blind spot in the bus, like any radio interference, may result in no bus warning. Due to penetration of the bumper antenna into the trunk area, the trunk lid may open without an external identification device.

SMART KEY Reminder 1

1. 1
   Preconditions:

   • All terminals OFF.
   • At least one door is open
   • Lock status not locked (checked periodically 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 fob is not active, SMK searches for fobs inside the vehicle. Same LF strategy as for ID-out warning must be used (registration only, no authentication)
   • IF fob IS ACTIVE, 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 the trunk) is open
   • No FOB-IN and lock status (checked periodically by SMK every 100 ms while CAN/LIN is active)
5. 5
   Vehicle action: Closes the last door or trunk with handles in the locked state or during locking
6. 6
   SMK actions: Within 500 ms after door closing, if all doors are locked, the following actions are performed:

   • 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 fob IS ACTIVE, 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
   Preconditions: While (at least one door handle is unlocked) & (ACC ON or IGN ON) & (No FOB-IN):

   • (All doors closed) and (trunk closed)
8. 8
   Event:

   • User presses the button on the door handle or trunk
9. 9
   SMK actions: The SMK searches for fobs outside the vehicle; the same LF strategy defined for the "Input/Output Difference Access" scenario must be used.
10. 10
    Preconditions: Same as the passive lock precondition, but at least one door is open.
11. 11
    Event: User presses the button on the door handle.
12. 12
    SMK actions: The SMK searches for fobs outside the vehicle; the same LF strategy defined for the "Input/Output Difference Access" scenario must be used. If no fob is found, no action is required. If the preconditions cease to be valid within the buzzer operating time (3 seconds), the SMK ECU immediately turns off the buzzer.
13. 13
    Preconditions: Same as the passive lock precondition
14. 14
    User action:

    • User presses the door handle button
15. 15
    SMK ECU actions:

    • If the ATWS (Anti-Theft Warning System) is in the DISARM state, the SMK ECU searches for a fob inside the vehicle (use "Door Lock"). Warning 3" scenario)
16. 16
    SMK Operation: While the preconditions are being met, the SMK ECU periodically searches for Smart Key fobs inside the vehicle. The LF strategy must be used, since it is defined for the 'no ID' warning (registration only, no authentication). Periodic search is performed every 3 seconds. If no fob is found, the SMK ECU activates the Smart Key warning lamp, since all preconditions are valid, and performs another search after 3 seconds.

Smart Key Reminder 2, Smart Key Door Lock Warning, Door Lock Warning 1, Door Lock Warning 2, Door Lock Warning 3. If the FOB is not found, passive locking is performed. If any valid FOB is detected, the SMK ECU activates the exterior buzzer. If the activity timer has expired, or ACC is ON, or IGN1 is ON, or NOT all doors are closed, or FOB-IN, the SMK ECU immediately turns off the buzzer. After searching for the interior FOB, the SMK ECU also searches for FOBs outside the vehicle. Smart Key Indicator Warning: If any valid FOB is detected, the SMK ECU stops the key indicator lamp from operating and (if one door is open) performs another search after 3 seconds; if no door is open, then only in the next cycle. When the preconditions remain valid, the search resumes when one door is opened. Fail-Safe Functions (Backup for Limp Home): In case of FOB battery discharge or transmission failure, 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 while the terminal is ON and a valid fob is inside the vehicle, SMK re-enables authentication and stops the warning. If the terminal is in ACC, SMK illuminates the immobilizer lamp.

If there is an LF error (LF overheating or LF antenna failure), the system will behave as if the fob was not found.

Immobilizer Lamp: When the PIF is removed from the MSL and reinstalled, and when the MSL handle is pressed, the lamp will illuminate again. FOB Low Battery Detection: To determine the FOB battery status, a battery voltage measurement and low-voltage detection strategy is implemented in the FOB. Battery voltage measurement will be performed if the FOB button is pressed or an LF measurement command is received. If the FOB detects low battery voltage, the LED will not light when the button is pressed. Teach-In Description: This section describes the teach-in procedure for the SMK and FOB. Teaching the SMK and FOB requires connection to a diagnostic tool. TEACH-IN MODE: In any mode, the teach-in process is controlled by the SMK. Before starting the teach-in service, the Fob-In signal must be active and the vehicle secret code (also called the PIN code) must be known. TEACH-IN 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 is already taught a specific PIN code. The PIN code is fixed for the entire service life of the vehicle, so the same PIN code must be used in this mode. Otherwise, the teach-in will be unsuccessful. TEACH-IN MODE: Procedure Description (Step by Step). Purpose: Key teach-in procedure at the service station. Initial condition:

• SMK replacement: SMK not learned, SMART FOB already learned with the same PIN code
• Learning additional or new keys: SMK and ESCL already learned with the same PIN code