ESC (Electronic Stability Control) System

Components and Components Location

COMPONENTS LOCATION

Description and Operation

ESC Description

Electronic Stability Control (ESC) detects dangerous driving situations, such as panic reactions in hazardous situations, and stabilizes the vehicle by braking individual wheels and intervening in engine control.

ESC adds another function to the ABS, TCS, EBD and ESC functions, known as Active Yaw Control (AYC). While the ABS/TCS function regulates wheel slip during braking and acceleration and thus significantly influences vehicle dynamics in the longitudinal direction, Active Yaw Control rotates the vehicle about its vertical axis.

This is done by intervening in the braking process of the individual wheel and adjusting the current engine torque, without the driver having to become active.

ESP mainly consists of three components: sensors, an electronic control unit and servo motors.

The stability control system operates under all driving and operating conditions. Under certain driving conditions, the ABS/TCS function may operate simultaneously with the ESC function, which is activated by the driver's command.

If the stability control function fails, the basic safety function, ABS, continues to be supported.

ESC Control Description

The ESC system includes the ABS/EBD, TCS and AYC functions.

ABS/EBD function: The ECU converts the active sensor signal (current volume) from the four wheel sensors into a square wave. Using the above signals, the ECU calculates the vehicle speed, acceleration and deceleration of the four wheels. In addition, the ECU determines whether the ABS/EBD system should be active or not.

The TCS function prevents wheel slip in the direction of travel. It applies brake pressure and reduces engine torque via CAN bus. The TCS function uses the wheel speed sensor signal to detect wheel slip. Operation is similar to that of ABS.

The AYC function prevents unstable vehicle maneuvering. To determine vehicle maneuvers, the AYC function uses signals from the maneuver sensors (yaw rate sensor, lateral acceleration sensor, steering wheel angle sensor).

If vehicle maneuvering is unstable (oversteer or understeer), the AYC function applies brake pressure to the specific wheel and sends a signal via CAN to reduce engine torque.

After the ignition is turned on, the ECU continuously diagnoses system malfunctions (self-diagnosis). When a system malfunction is detected, the ECU informs the driver through the BRAKE/ABS/ESC warning lamp due to system malfunction (safety warning).

ENTRY/EXIT PLAN

ECU Operating Mode

ECU Hydraulic Circuit Diagram

1. 1

   ESC No function: normal braking.

   solenoid valve	passage	Valve	pump	TC valve
   Inlet (NO)	Outside	Open	Outside	Outside
   Outlet (NC)	Outside	close

2. 2

   Cruise Control Operation

   solenoid valve		passage	Valve	pump	TC valve
   Understeer (Rear wheel only)	Inlet (NO)	Outside	Open	A	A
   	Outlet (NC)	Outside	close
   excessive oversteer (Front wheel outside only)	Inlet (NO)	Outside	Open
   	Outlet (NC)	Outside	close

   
   

   

ABS Warning Lamp Module

The ABS warning lamp module also has a self-check function. ABS malfunction. The ABS warning lamp illuminates under the following conditions:

• During the initialization phase after ignition ON (continuously for 3 seconds).

• When the ABS function is disabled due to a fault.

• In diagnostic mode.

• When the ECU connector is disconnected from the ECU.

• The instrument cluster illumination comes on when data communication with the CAN module is not possible.

PARKING BRAKE / EBD WARNING LAMP MODULE

The EBD warning lamp module also has a self-check function. EBD fault status. However, when the parking brake switch is turned on, the EBD warning lamp illuminates regardless of the operating status of the EBD system. The EBD warning lamp illuminates under the following conditions:

• During the initialization phase after ignition ON (continuously for 3 seconds).

• When the parking brake switch is on or the brake fluid level is low.

• When the EBD function is faulty.

• In diagnostic mode.

• When the ECU connector is disconnected from the ECU.

• The instrument cluster illumination comes on when data communication with the CAN module is not possible.

ESC Function/Warning Lamp

The ESC function/warning lamp indicates self-check as well as an ESC malfunction.

The ESC function lamp illuminates under the following conditions:

• During the initialization phase after ignition ON (continuously for 3 seconds).

• If the ESC function is locked due to a system malfunction.

• When ESC control is operating (flashes at 2 Hz).

• In diagnostic mode (except standard mode)

• The instrument cluster illumination comes on when data communication with the CAN module is not possible.

ESC lamp off

The ESC Off indicator lamp indicates self-check as well as an ESC malfunction.

The ESC Off indicator lamp illuminates under the following conditions:

• During the initialization phase after IGN ON (continuously for 3 seconds).

• The ESC Off indicator lamp illuminates when the driver operates the ESP switch.

ESC ON/OFF SWITCH

The ESC ON/OFF switch is used to switch the ESC function on and off according to the driver's input signal.

The ON/OFF switch is a momentary contact switch. Contact closure activates the ignition.

The ESC function is initially on, and the state is set by the toggle switch.

Schematic diagrams

Circuit diagram

TERMINAL DESCRIPTION