ELECTRIC PARKING BRAKE SYSTEM


  1. FUNCTION OF MAIN COMPONENTS

    Component Function
    Rear Disc Brake Caliper Assembly Parking Brake Actuator Assembly Controls the brake pad position by operating the motor according to signals from the parking brake ECU assembly and locks or releases the parking brake.
    Electric Parking Brake Switch Assembly Electric Parking Brake Switch

    • Sends the lock or release operation signal to the parking brake ECU assembly.

    • Switches between the manual function and auto function.
    Indicator Light Lights up to inform the driver that the parking brake has locked.
    AUTO Indicator Light Lights up to inform the driver that control via the auto function is possible.
    Combination Meter Assembly Parking Brake Warning Light

    • Lights up to inform the driver that the parking brake has locked.

    • Blinks to inform the driver that the electric parking brake system is not available.
    Brake Warning Light (Yellow Indicator) Lights up to inform the driver that the electric parking brake ECU assembly detected a malfunction in the system.
    Multi-information Display

    • Informs the driver that the electric parking brake ECU assembly has a malfunction in the system.

    • Displays the switching between the manual function and auto function.
    Master Warning Light Informs the driver that the electric parking brake ECU assembly has a malfunction in the system.
    Buzzer Sounds together with the indication of the multi-information display and the illumination of the master warning light in order to inform the driver of a malfunction in the electric parking brake system.
    Yawrate Sensor Assembly Deceleration Sensor Detects the gradient of the road surface by detecting the inclination of the vehicle.
    Parking Brake ECU Assembly Controls the motor in the parking brake actuator assembly based on information from the electric parking brake switch, the built-in current sensor and each ECU.
    Hybrid Vehicle Control ECU Assembly Transmits the shift lever position to the parking brake ECU assembly.
    Skid Control ECU ASSEMBLY Transmits the speed sensor, regulator pressure sensor and brake pedal stroke sensor assembly signals to the parking brake ECU assembly.

  2. SYSTEM CONTROL


    1. The parking brake ECU assembly locks or releases the parking brake by controlling the rotation direction and drive current of the motor built into the parking brake actuator assembly based on signals from the electric parking brake switch and each ECU.

    2. The parking brake ECU assembly detects the operation condition of the motor via the built-in current sensor.

  3. FUNCTION


    1. Manual Function


      1. When the electric parking brake switch is pulled with the vehicle stopped, the parking brake ECU assembly operates the motor in the parking brake actuator assembly to lock the parking brake. At this time, the parking brake ECU assembly generates braking force according to the road surface by calculating the road grade based on the signal from the deceleration sensor and controlling the motor drive current.

      2. When the brake pedal is depressed, and then the electric parking brake switch is pushed, the parking brake ECU assembly operates the motor in the parking brake actuator assembly in reverse to release the parking brake.

      3. The motor in the parking brake actuator assembly operates to generate braking force only while the electric parking brake switch is pulled when the vehicle is in motion. When the electric parking brake switch is released, the motor in the parking brake actuator assembly operates in reverse to decrease the braking force.

      4. The parking brake lock operation can be operated regardless of whether the power switch is turned on (IG) or off.

      5. The parking brake can be released when the power switch is turned on (IG).

      6. When a malfunction occurs with the electric parking brake switch, the auto function automatically turns on.

    2. Auto Function


      1. The manual function can be switched to the auto function via operation of the electric parking brake switch. When parking brake control via the auto function is possible, the AUTO indicator light located next to the electric parking brake switch illuminates.

      2. When the electric parking brake switch is pulled and held for 5 seconds or more with the parking brake locked, the auto function turns on. Then a warning is displayed on the multi-information display indicating that the auto function is on.

      3. When the electric parking brake switch is pushed and held for 5 seconds or more with the parking brake released, the auto function turns off. Then a warning is displayed on the multi-information display indicating that the auto function is off.

      4. When the driver moves the shift lever from a position other than P to P with the auto function on, the parking brake ECU assembly operates the motor in the parking brake actuator assembly to lock the parking brake. Also, when the shift lever is moved from P to a position other than P with the brake pedal depressed, the parking brake is released.

    3. Backup Function


      1. The electric parking brake system automatically operates the motor in the parking brake actuator assembly to maintain the vehicle parked position in the following conditions.


        • When a malfunction occurs in the brake hold function while the vehicle is stopped via operation of the brake hold function.

        • When a brake operation is not performed for 3 minutes while the vehicle is stopped via operation of the brake hold function.

        • When a malfunction occurs in the brake hold function while the dynamic radar cruise control system holds the vehicle parked position (brake hold function operating)

  4. FAIL-SAFE


    1. When a malfunction has occurred in the system, the manual function maintains as much control as possible.

    2. When a malfunction has occurred in the system, the auto function and backup function prohibits control.

      Tech Tips

      When a malfunction occurs with the electric parking brake switch, parking brake control via the auto function is maintained.

    3. When the parking brake cannot be released due to the fail-safe state or a malfunction in the power source system, the parking brake can be released by supplying power to the electric release connector. For details, refer to the Repair Manual.

    4. When the parking brake cannot be released due to a mechanical malfunction, the parking brake can be released by removing the brake actuator assembly from the brake caliper. For details, refer to the Repair Manual.

  5. DIAGNOSIS


    1. If a malfunction is detected in the system, the parking brake ECU assembly will alert the driver by illuminating the brake warning light (yellow indicator) in the combination meter assembly and outputting a warning message on the multi-information display.

    2. At the same time, Diagnosis Trouble Codes (DTCs) are stored in the memory. The DTCs stored in the parking brake ECU assembly are output to a Global TechStream (GTS) connected to the DLC3. For details, refer to the Repair Manual.