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 Trunk Lid Switch
• 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
   Start Button. The system allows the user to switch power modes (OFF, ACC, ON) and to start and stop the vehicle engine without performing any action with the SMART KEY fob. Refer to Engine Start 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 ECU (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 to other vehicle devices. To communicate with the SMART KEY FOB, the SMK ECU generates a request (challenge) as an encoded and modulated 125 (or 134.2) kHz signal 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 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 (or 134.2) kHz magnetic field, which carries 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 luggage compartment or tailgate. Up to three antennas cover the vehicle interior and the luggage compartment or tailgate: two in the cabin and one in the luggage compartment.
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).

Door handle The front door handles of both doors (driver/passenger door) are equipped with LF transmitting antennas for emitting 125 (or 134.2) kHz. The front door handles are also equipped with a push button. The push 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 challenge sent from the vehicle through the exterior antennas in the free space within a minimum radius of 0.7 m around the exterior antennas built into the door handle; refer to the illustration below. The SMART KEY FOB receives and interprets the challenge sent from the vehicle through the exterior antennas in the 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 locked doors indicate 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 switch when the trunk lid is closed indicates the operator's intention to open the trunk lid, and thus activates the system. The SMK ECU then sends an LF challenge to the SMART KEY FOB through the bumper exterior antenna. The SMART KEY FOB responds with an RF response. If the received response matches the expected response, the SMK ECU sends the message "trunk open" 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 fob is ACTIVE, SMK sends a PDM request to search 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 fob is ACTIVE, SMK sends a PDM request to search 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 no fob is 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 operation. The indicator lamp turns off and (if one door is open) performs another search after 3 seconds; if no door is open, then only in the next search. When the preconditions remain valid, the search resumes by opening one door. 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 the ID OUT WNG message via CAN (external buzzer warning and internal buzzer warning).
   • 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.

Immobilizer Lamp When the PIF is removed from the MSL and reinstalled, and when the MSL handle is pressed, the lamp will light again. Fob Low Battery Detection To determine the fob battery status, the defined battery voltage measurement and low voltage detection strategy is implemented in the fob. Battery voltage measurement will be performed when the fob button is pressed or an LF measurement command is received. If the fob detects a low battery voltage, the LED will not light when the button is pressed. Learning Description This chapter describes the learning procedure for the SMK and FOB. A connection to the diagnostic tool is required to learn the SMK and fobs. 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 the existing system. This means the system has already been learned with 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, learning will fail. LEARNING MODE Procedure Description (Step by Step) Purpose: Key learning 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 must be in original condition (Smart Key, IPM, ECM).
• Depress the brake pedal in P or N range
• Press the start button once with the virgin smart key.