Parking Brake System: Description and Operation

Description

The EPB is an electronic parking brake.
The EPB is different from existing parking systems which operated with the brake pedal or the lever type. The EPB system sends the signal to the ECU when a driver operates the EPB switch. The ECU operates the EPB actuator composed with motor gears. The braking power is caused by occurs when the motor pulls the cable connected the brake system.
The EPB ECU is one of the parts of EPB system. It perceives the signal of the various sensor of system, executes a self diagnosis, controls EPB system with the logic.

Main function
1. Static Braking Mode
The operation and the cancellation at the stop condition of the vehicle
(1) The operation condition: Push the EPB switch irrespective of the ignition switch ON & the brake pedal pressed condition. (Push).
A. The Vehicle speed <= 3kph
(2) The cancellation condition: Pull the EPB switch at the ignition switch on & the brake pedal pressed condition. (Pull).
2. Dynamic Braking Function
DBF (Dynamic Braking Function): The DBF is the braking function at the driving condition, it can operate the EPB system and cancel it at the vehicle driving condition. This function will be used while foreign materials get in between the brake pedal or the brake hydraulic line can not be operated.
(1) The operation condition
It operated only when the vehicle speed is faster than 3kph and the EPB switch is pushed.
(2) The cancellation condition: It canceled when the pushing of the EPB switch is stopped.
(3) Principle of Operation
A. VDC system is normal condition: EPB requests applying pressure of brake to VDC system.
B. VDC system is abnormal condition: EPB operates the parking brake for reduction of speed.
(4) Peculiarity
Anti-lock is operated when occurring wheel lock. Parking lamp on the cluster is flickered in the case of emergency braking.
3. Drive Away Release (DAR)
DSR is auto release function of parking brake to start the vehicle smoothly when a driver pedals an acceleration pedal at the D/R/S range in the EPB mode. DAR prevents slipping of the vehicle when starting in the a slope way with controlling braking power for parking.
(1) Disallowance condition of Drive Away Release (DAR)
If even occurred one of the condition below, EPB will be able to be released automatically. (Safety Concept)
A. In the case of opening driver door (A driver can check it on the cluster)
B. When driver doesn't wear the seat belt (A driver can check it on the cluster)
C. In the case of opening the bonnet of the vehicle (A driver can't check it on the cluster)
D. In the case of opening the trunk of the vehicle (A driver can check it on the cluster)
(2) If a driver attempts starting a vehicle by pedaling an acceleration pedal at the D/ S/ R range in the disallowance condition of DAR, the message will be displayed as "Auto-Release Condition Not Met. Manual Release possible by EPB Switch." with warning sound."
4. Engine-Off Apply
Automatic operation function in case of turning ignition switch off.
Parking lamp is displayed in the cluster during 15 seconds after turning ignition switch off.
(1) Process for inhibiting automatic operation of EPB when turning ignition switch off. (In case of "N" range parking )
A. Hit the brake pedal.
B. Pull the EPB switch.
C. Turn ignition switch off within 5 seconds after pulling the EPB switch.
5. Emergency Release
Emergency release is forced release function with pulling ERC (Emergency Release Cable) when normal release process of EPB system doesn't operated.
It needs in case of discharge of battery or break down of EPB system in the EPB operation.
Emergency release handle is located in the trunk. (Accessory tool box)
Connect the handle to the emergency release cable in the trunk. Pull the cable upward up to occurring "click" sound.

CAUTION:
1. Message is displayed in the cluster with flickering EPB lamp when emergency release is sensed.
2. EPB switch must be operate when the vehicle is restored to normal.
3. Emergency release function is usually prohibited except particular inspection.
4. When unavoidable, must operate emergency release function in the P-range on the flat after supporting the wheel with the square lumber.

6. Latching Run
This is reconnection function to operate EPB normally after emergency release.
Operation
(1) After emergency release, when operating EPB first, the hook connects to the claw in the EPB with operating parking brake with maximum cable tension.
(2) Reconnection function can be performed with the scantool.
(3) After testing for reconnection 5 times, EPB isn't be operated in the present ignition switch cycle when EPB doesn't reconnect normally.
7. Safety Clutch
Safety clutch protects EPB system. Safety clutch is operated to protect the gear box and the motor when operating EPB over the maximum allowance stroke. Noisy sound occurred when operating safety Clutch. This function occurred in case of fault of connection between the parking brake and EPB cable.
8. AVH(Automatic Vehicle Hold)
AVH supports to keep a stop condition of the vehicle by hydraulic brake at a stop.
(1) Condition for operation
A. Engine run
B. AVH switch ON.
C. Closing driver door
D. Fastening driver seat belt
E. A gear shift is not P-range
F. Perfect stop condition with hitting the brake pedal.
(2) AVH function holds stop condition of the vehicle for maximum 5 minutes.
VDC valve keeps stop condition because of intercept the oil passage with pressure occurred from brake pedal.
(3) An accumulated time of AVH operation : Max. 30min
(4) Automatic release function
AVH mode is released when driver attempts starting a vehicle by pedaling an acceleration pedal at the D/ S/ R range.
(5) Automatically convert AVH to EPB
AVH will convert EPB operation automatically if any one satisfy conditions below.
[Normal conversion case]
A. In the case of driver door open & Driver seat belt release at the same time
B. In the case of opening the bonnet of the vehicle
C. In the case of opening the trunk of the vehicle
D. In the case of over 5 minutes of AVH operation time
E. Engine off
F. Stop at a slope of twenty five degrees
[Abnormal conversion case]
A. When sensing detailed motion of the vehicle.
B. When sensing the fault of VDC hydraulic system.