Parking Brake System: Description and Operation

PARKING BRAKE: ELECTRIC PARKING BRAKE SYSTEM: SYSTEM DESCRIPTION

SYSTEM DESCRIPTION

1. SYSTEM DESCRIPTION
The electric parking brake system controls the parking brake cable by electrically loosening and tightening the cable with the actuator. The main functions are as follows:

- The parking brake lock/release control is performed by manually operating the electric parking brake switch.
- When the AUTO switch is ON, the parking brake lock/release control operates according to the shift lever position (moved from position other than P to P position: lock; move from P to position other than P: release).
- If 3 minutes have passed after stopping the vehicle with the brake hold switch ON (driver door is open, driver side seat belt is unfastened, engine hood is open or trunk is open), the parking brake lock automatically operates. (This is a backup operation of the electronically controlled brake system)
HINT: The parking brake lock automatically operates even if CAN communication is blocked, or the electronically controlled brake system malfunctions while the vehicle is stopped.

(a) The standard parking brake lock/release controls (while vehicle is stopped) are as follows:
(1) The lock control will tighten the parking brake cable to increase tension. The tension will be increased to the target value based on the tilt of the vehicle according to the yaw rate sensor. If the cable tension reaches the target value, the lock control stops tightening the cable and maintains this cable tension.
(2) The release control loosens the cable until the parking brake cable tension reaches a specified value.
(b) While the vehicle is being driven, the lock control only operates while the electric parking brake switch is being pushed. The release control operates immediately after the switch is released.
2. COMPONENT OPERATION
(a) Electric parking brake ECU
(1) The electric parking brake ECU operates the parking brake actuator to lock or release the parking brake according to the shift lever position, signals and conditions through CAN communication, and switch operations from the driver.
(b) Electric parking brake actuator
(1) The electric parking brake actuator controls the parking brake by tightening and loosening the parking brake cable according to signals from the electric parking brake ECU.
(c) Tension sensor
(1) The tension sensor is built into the electric parking brake actuator and outputs the tension value of the parking brake cable to the electric parking brake ECU.
(d) Electric parking brake switch
(1) Lock switch
- Detects the lock operation from the driver, and outputs a signal to the electric parking brake ECU.
(2) Release switch
- Detects the release operation from the driver, and outputs a signal to the electric parking brake ECU.
(3) AUTO switch
- Detects an AUTO function ON/OFF change from the driver, and outputs a signal to the electric parking brake ECU.
(4) AUTO switch light
- The AUTO switch light informs the driver if the shift-linked function is possible or not.
(5) Brake warning light / yellow (minor malfunction)
- The brake warning light / yellow (minor malfunction) is used by the parking brake ECU and skid control ECU. If the electric parking brake system is malfunctioning or a problem in another system causes the parking brake function to be limited, this light informs the driver. This light also illuminates for 3 seconds after the power switch is turned ON (IG).
(6) Parking brake indicator light (RED)
- When the parking brake is locked, the parking brake indicator light (RED) illuminates. Also, if the driver attempts to operate the electric parking brake when operation is not possible, the light blinks. The light also blinks when the cable loosens due to an outside influence.
(7) Multi-information display
- If a malfunction occurs in the electric parking brake system and the system control is not possible, the brake warning light / yellow (minor malfunction) and multi-information display are used to inform the driver. The multi-information display is also used to display cautions.

PARKING BRAKE: ELECTRIC PARKING BRAKE SYSTEM: SYSTEM DIAGRAM

SYSTEM DIAGRAM