Brake System

Electric Parking Brake (EPB) Description and Operation

9steps
~54min
2/5difficulty
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Description

EPB is an electronic parking brake. EPB differs from conventional parking systems, which use a foot pedal or lever type. The EPB system sends a signal to the ECU when the driver presses the EPB switch. The ECU operates the EPB actuator, which consists of geared motors. The EPB has several functions.
  • Static Apply
  • Emergency braking function due to hydraulic brake malfunction
  • Automatic Apply
EPB Function
  1. Switch operation while stationary (Static Park)
    • Manually apply the parking brake by pressing the EPB switch while the vehicle is stationary.
    • With the ignition on, the parking brake is applied with reduced clamping force on a grade of less than 8%.
    • Except as described above, it is always applied with full clamping force.
  2. Switch release while stationary (Static Release)
    • Release the parking brake manually by pressing the EPB switch while the vehicle is stationary.
    • For safety, it is released only when the ignition is on and the brake pedal is depressed.
  3. Dynamic Emergency Braking (Dynamic Braking)
    • Electronic Controlled Deceleration (ECD): When the EPB switch is operated while driving, a request is sent to the VDC only while the switch is operated, so that hydraulic braking is performed by the VDC instead of the EPB actuator.
    • Rear Wheel Unlock (RWU): If the VDC is not operating normally (VDC Fail) when the EPB switch is operated while driving, and wheel speed information can be obtained, the EPB actuator will apply braking only while the switch is operated to ensure safe deceleration.
    • Slow Release Upon (SRU): If the VDC is not operating normally (VDC Fail) when the EPB switch is operated while driving, and wheel speed information cannot be obtained, the EPB will automatically increase the parking force gradually to perform braking only while the switch is operated.
  4. Automatic EPB Apply (Auto Apply)
    • Stop the vehicle with Automatic Vehicle Hold (AVH) function enabled, and the EPB will be applied automatically when the engine is turned off.
  5. Automatic EPB Release (Release on Acceleration)
    • The parking brake is automatically released when the accelerator pedal is depressed while the EPB is applied.
    • For safety, automatic release occurs only when all of the following conditions are met:
    1. Engine running
    2. The seat belt is fastened.
    3. Driver's door, trunk and hood are closed.
    • To prevent the vehicle from rolling down a slope, it is released automatically only after a torque above a certain level, based on the grade, has been generated.
  6. Re-application of EPB force when the vehicle moves downhill (Roll-back Re-clamping)
    • Additional EPB force is generated when downhill vehicle movement is detected after EPB force has been applied.
    • With the engine off, this function is active only when wheel speed information can be obtained (that is, within 3 minutes after the engine is turned off).
  7. P to X (Automatic EPB Force Release for Gear Shifting): When the shift lever is moved from P or N to D or R, the parking brake is automatically released. However, this is possible only when the engine is running and the brake pedal is depressed, to ensure safe automatic release.
Auto Hold keeps the vehicle stationary even when the brake pedal is released after the driver has brought the vehicle to a complete stop by depressing the brake pedal. Auto Hold does not operate when:
  • Driver's seat belt unfastened, driver's door open
  • Engine hood open
  • Liftgate open
  • The shift lever is in P (Park).
  • EPB applied
For your safety, the Auto Hold function automatically switches to EPB in the following cases:
  • Driver's seat belt unfastened, driver's door open
  • Engine hood open
  • Liftgate open
  • Vehicle stationary for more than 10 minutes
  • Vehicle stationary on a steep slope for a long period of time
  • Vehicle has been driven several times
  1. Set
    1. With the driver's door, engine hood and trunk closed, fasten the driver's seat belt or depress the brake pedal, then press the AUTO HOLD button. The white AUTO HOLD indicator will illuminate and the system will be in standby mode.
    2. When you bring the vehicle to a complete stop by depressing the brake pedal, the AUTO HOLD indicator changes color from white to green.
    3. The vehicle will remain stationary even if you release the brake pedal.
    4. If EPB is applied, Auto Hold is canceled and the indicator turns white.
  2. Cancellation: If you want to cancel it manually, pull the EPB switch while depressing the brake pedal. The AUTO HOLD indicator changes color from green to white, and the system goes into standby mode. For your safety, cancel the Auto Hold function manually if the vehicle ahead is too close or when driving downhill.

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