Scheme 10
Scheme 11
Description of ESC
Optimum driving safety now has a name: ESC, the Electronic Stability Control.
ESC recognizes critical driving conditions, such as panic reactions in dangerous situations, and stabilizes the vehicle by wheel-individual braking and engine control intervention.
ESC adds a further function known as Active Yaw Control (AYC) to the ABS, TCS, EBD and EDC functions. Whereas the ABS/TCS function controls wheel slip during braking and acceleration and, thus, mainly intervenes in the longitudinal dynamics of the vehicle, active yaw control stabilizes the vehicle about its vertical axis.
This is achieved by wheel individual brake intervention and adaptation of the momentary engine torque with no need for any action to be taken by the driver.
ESC essentially consists of three assemblies: the sensors, the electronic control unit and the actuators.
The stability control feature works under all driving and operating conditions. Under certain driving conditions, the ABS/TCS function can be activated simultaneously with the ESC function in response to a command by the driver.
In the event of a failure of the stability control function, the basic safety function, ABS, is still maintained.
Scheme 12
Description of ESC Control
ESC system includes ABS/EBD, TCS and AYC function.
ABS/EBD function The ECU changes the active sensor signal (current shift) coming from the four wheel sensors to the square wave.
By using the input of above signals, the ECU calculates the vehicle speed and the acceleration & deceleration of the four wheels.
And, the ECU judges whether the ABS/EBD should be actuated or not.
TCS function prevents the wheel slip of drive direction by adding the brake pressure and engine torque reduction via CAN communication.
TCS function uses the wheel speed sensor signal to determine the wheel slip as far as ABS function.
AYC function prevents unstable maneuver of the vehicle. To determine the vehicle maneuver, AYC function uses the maneuver sensor signals (Yaw Rate Sensor, Lateral Acceleration Sensor, Steering Wheel Angle Sensor).
If vehicle maneuver is unstable (Over Steer or Under Steer), AYC function applies the brake pressure on certain wheel, and send engine torque reduction signal by CAN.
After the key-on, the ECU continually diagnoses the system failure. (Self-diagnosis)
If the system failure is detected, the ECU informs driver of the system failure through the BRAKE/ABS/ESC warning lamp, (fail-safe warning)
Scheme 13
Scheme 14
Scheme 15
Scheme 16
Scheme 17
- ESC Non-operation: Normal braking. SOLENOID VALVE CONTINUITY ESC (NON-OPERATION: NORMAL BRAKING) Solenoid valve Continuity Valve Motor pump TC Valve IN (NO) OFF OPEN OFF OFF OUT (NC) OFF CLOSE Operation In this position, the inlet valve and the TCS valve are open, the electrically operated shuttle valve and the outlet valve are closed. * ESV: Electric reversing valve.
- ESC operation SOLENOID VALVE CONTINUITY (ESC OPERATION) Solenoid valve Continuity Valve Motor pump TC Valve Under steering (Only inside of rear wheel) IN(NO) OFF OPEN ON ON OUT(NC) OFF CLOSE Over steering (Only outside of front wheel) IN(NO) OFF OPEN OUT(NC) OFF CLOSE Operation The on/off booster builds up a pressure of approx. 10 bar in order to enable the ESC pump to suck brake fluid at low temperatures. In this position, the inlet valve is driven in a pulsed cycle. The TCS valve is closed. The outlet valve remains closed. The electrically operated shuttle valve is opened. The hydraulic pressure is led to the wheel brakes which are to be applied for a brief period of time.
Scheme 18
Scheme 19
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Scheme 21
- Normal Braking SOLENOID VALVE (NORMAL BRAKING) Solenoid valve State Valve Passage Inlet valve (NO) OFF OPEN Master cylinder Wheel cylinder Outlet valve (NC) OFF CLOSE Wheel cylinder Reservoir When braking, the hydraulic pressure in the TMC is increased. The pressure reaches the wheel brake via the current less open inlet valve IV. The current less closed outlet valve OV is closed. For the sake of simplicity the diagram is limited to only the solenoid valve pair of one brake circuit. The wheel speed is reduced as the brake pressure increases, in the extreme case until the wheel locks.
- Dump Mode SOLENOID VALVE (DUMP MODE) Solenoid State Valve Passage Inlet valve (NO) ON CLOSE Master cylinder Wheel cylinder Outlet valve (NC) ON OPEN Wheel cylinder Reservoir If the wheel speed decreases, there is still a tendency to lock; the brake pressure on the corresponding wheel must be reduced accordingly. For this, the outlet valve OV is opened, the inlet valve IV remains closed. The brake pressure to the low-pressure accumulator is reduced. The wheel in danger of locking gains speed again.
- Hold Mode SOLENOID VALVE (HOLD MODE) Solenoid State Valve Passage Inlet valve (NO) ON CLOSE Master cylinder Wheel cylinder Outlet valve (NC) OFF CLOSE Wheel cylinder Reservoir When a wheel (or several) tends to lock the inlet valve IV is first closed to avoid a further increase in brake pressure. The outlet valve OV remains closed: the brake pressure is kept constant.
- Increase Mode SOLENOID VALVE (INCREASE MODE) Solenoid State Valve Passage Inlet valve (NO) OFF OPEN Master cylinder Wheel cylinder Outlet valve (NC) OFF CLOSE Wheel cylinder Reservoir For optimum brake from the certain wheel acceleration a brake pressure increase is necessary. For this, the inlet valve IV is opened and the outlet valve OV is closed. The pump of the unit starts to run and aspirates the necessary quantity of fluid from the Low-pressure accumulator, in order to produce the necessary brake pressure for the pressure increase phase in seconds. With an increase in the brake pressure the wheel speed is reduced. These control phases are repeated until the ABS control unit no longer detects any tendency of the wheels to lock. NOTE: During ABS control function, the brake pedal only moves in accordance with the volume requirement of the wheels. Because of a sudden change in friction coefficient this pedal movement may increase slightly.
Scheme 22
The active ABS warning lamp module indicates the self test and failure status of the ABS The ABS warning lamp shall be on
- During the initialization phase after IGN ON. (Continuously 3 seconds).
- In the event of inhibition of ABS functions by failure.
- During diagnostic mode.
- When the ECU Connector is separated from ECU.
EBD (Electronic Brake-Force Distribution) Operation
The EBD system (Electronic Brake force Distribution) as a sub-system of the ABS system is to control the effective adhesion utilization by the rear wheels.
It further utilizes the efficiency of highly developed ABS equipment by controlling the slip of the rear wheels in the partial braking range.
The brake force is moved even closer to the optimum and controlled electronically, thus dispensing with the need for the proportioning valve.
The proportioning valve, because of a mechanical device, has limitations to achieve an ideal brake force distribution to the rear wheels as well as to carry out the flexible brake force distribution proportioning to the vehicle load or weight increasing. And in the event of malfunctioning, driver cannot notice whether it fails or not.
EBD controlled by the ABS Control Module, calculates the slip ratio of each wheel at all times and controls the brake pressure of the rear wheels not to exceed that of the front wheels.
If the EBD fails, the EBD warning lamp (Parking brake lamp) lights up.
General Description
The ESC system is the shorten word of Electronic Stability Control system. This system recognizes a critical driving condition by Yaw-rate sensor, Lateral acceleration sensor and Steering angle sensor. And then it stabilizes the vehicle by a individual wheel braking and engine torque control through CAN communication. The ESC ECU (HECU, Hydraulic and Electronic Control Unit) checks the battery voltage and alternator output voltage to determine, as a safety issue, whether this system can operate normally or not. The normal battery voltage range is essential for controlling this system as intended.
DTC Description
The HECU monitors the voltage of battery and if it stays more than 17 Volts, this DTC is set.
The ESC system is the shorten word of Electronic Stability Control system. This system recognizes a critical driving condition by Yaw-rate sensor, Lateral acceleration sensor and Steering angle sensor. And then it stabilizes the vehicle by a individual wheel braking and engine torque control through CAN communication. The ESC ECU (HECU, Hydraulic and Electronic Control Unit) checks the battery voltage and alternator output voltage to determine, as a safety issue, whether this system can operate normally or not. The normal battery voltage range is essential for controlling this system as intended.
The HECU monitors the voltage of battery and if it stays below certain value, this DTC is set.
The ESC system is the shorten word of Electronic Stability Control system. This system recognizes a critical driving condition by Yaw-rate sensor, Lateral acceleration sensor and Steering angle sensor. And then it stabilizes the vehicle by a individual wheel braking and engine torque control through CAN communication. Among components of this system, the wheel speed sensor (WSS) is the essential component of the brake system. The ESC ECU(HECU, Hydraulic and Electronic Control Unit) uses the wheel speed sensor's signals to calculate a vehicle speed and also to determine whether a wheel lock occurs or not.
The HECU monitors the wheel speed sensor's circuit and If it's signal current is continuously out of the specified range, this DTC is set.
The ESC system is the shorten word of Electronic Stability Control system. This system recognizes a critical driving condition by Yaw-rate sensor, Lateral acceleration sensor and Steering angle sensor. And then it stabilizes the vehicle by a individual wheel braking and engine torque control through CAN communication. Among components of this system, the wheel speed sensor(WSS) is the essential component of the brake system. The ESC ECU(HECU, Hydraulic and Electronic Control Unit) uses the wheel speed sensor's signals to calculate a vehicle speed and also to determine whether a wheel lock occurs or not.
The HECU monitors the wheel speed sensor's signal and If its signal is abnormally changed or the signal equivalent to 411 km/h is detected, this DTC is set.
The ESC system is the shorten word of Electronic Stability Control system. This system recognizes a critical driving condition by Yaw-rate sensor, Lateral acceleration sensor and Steering angle sensor. And then it stabilizes the vehicle by a individual wheel braking and engine torque control through CAN communication. Among components of this system, the wheel speed sensor(WSS) is the essential component of the brake system. The ESC ECU(HECU, Hydraulic and Electronic Control Unit) uses the wheel speed sensor's signals to calculate a vehicle speed and also to determine whether a wheel lock occurs or not.
The HECU monitors the wheel speed sensor signal continuously and if the signal of a wheel speed sensor is omitted or too low, this DTC is set.
The ESC system is the shorten word of Electronic Stability Control system. This system recognizes a critical driving condition by Yaw-rate sensor, Lateral acceleration sensor and Steering angle sensor. And then it stabilizes the vehicle by a individual wheel braking and engine torque control through CAN communication. Among components of this system, the wheel speed sensor(WSS) is the essential component of the brake system. The ESC ECU (HECL), Hydraulic and Electronic Control Unit) uses the wheel speed sensor's signals to calculate a vehicle speed and also to determine whether a wheel lock occurs or not.
The HECU monitors the wheel speed sensor's circuit and If it's signal current is continuously out of the specified range, this DTC is set.
The ESC system is the shorten word of Electronic Stability Control system. This system recognizes a critical driving condition by Yaw-rate sensor, Lateral acceleration sensor and Steering angle sensor. And then it stabilizes the vehicle by a individual wheel braking and engine torque control through CAN communication. Among components of this system, the wheel speed sensor(WSS) is the essential component of the brake system. The ESC ECU (HECL), Hydraulic and Electronic Control Unit) uses the wheel speed sensor's signals to calculate a vehicle speed and also to determine whether a wheel lock occurs or not.
The HECU monitors the wheel speed sensor's signal and If its signal is abnormally changed or the signal equivalent to 411 km/h is detected, this DTC is set.
The ESC system is the shorten word of Electronic Stability Control system. This system recognizes a critical driving condition by Yaw-rate sensor, Lateral acceleration sensor and Steering angle sensor. And then it stabilizes the vehicle by a individual wheel braking and engine torque control through CAN communication. Among components of this system, the wheel speed sensor(WSS) is the essential component of the brake system. The ESC ECU(HECU, Hydraulic and Electronic Control Unit) uses the wheel speed sensor's signals to calculate a vehicle speed and also to determine whether a wheel lock occurs or not.
The HECU monitors the wheel speed sensor signal continuously and if the signal of a wheel speed sensor is omitted or too low, this DTC is set.
The ESC system is the shorten word of Electronic Stability Control system. This system recognizes a critical driving condition by Yaw-rate sensor, Lateral acceleration sensor and Steering angle sensor. And then it stabilizes the vehicle by a individual wheel braking and engine torque control through CAN communication. Among components of this system, the wheel speed sensor(WSS) is the essential component of the brake system. The ESC ECU(HECU, Hydraulic and Electronic Control Unit) uses the wheel speed sensor's signals to calculate a vehicle speed and also to determine whether a wheel lock occurs or not.
The HECU monitors the wheel speed sensor's circuit and If it's signal current is continuously out of the specified range, this DTC is set.
The ESC system is the shorten word of Electronic Stability Control system. This system recognizes a critical driving condition by Yaw-rate sensor, Lateral acceleration sensor and Steering angle sensor. And then it stabilizes the vehicle by a individual wheel braking and engine torque control through CAN communication. Among components of this system, the wheel speed sensor(WSS) is the essential component of the brake system. The ESC ECU(HECU, Hydraulic and Electronic Control Unit) uses the wheel speed sensor's signals to calculate a vehicle speed and also to determine whether a wheel lock occurs or not.
The HECU monitors the wheel speed sensor's signal and If its signal is abnormally changed or the signal equivalent to 411 km/h is detected, this DTC is set.
The ESC system is the shorten word of Electronic Stability Control system. This system recognizes a critical driving condition by Yaw-rate sensor, Lateral acceleration sensor and Steering angle sensor. And then it stabilizes the vehicle by a individual wheel braking and engine torque control through CAN communication. Among components of this system, the wheel speed sensor(WSS) is the essential component of the brake system. The ESC ECU(HECL), Hydraulic and Electronic Control Unit) uses the wheel speed sensor's signals to calculate a vehicle speed and also to determine whether a wheel lock occurs or not.
The HECU monitors the wheel speed sensor signal continuously and if the signal of a wheel speed sensor is omitted or too low, this DTC is set.
The ESC system is the shorten word of Electronic Stability Control system. This system recognizes a critical driving condition by Yaw-rate sensor, Lateral acceleration sensor and Steering angle sensor. And then it stabilizes the vehicle by a individual wheel braking and engine torque control through CAN communication. Among components of this system, the wheel speed sensor(WSS) is the essential component of the brake system. The ESC ECU(HECU, Hydraulic and Electronic Control Unit) uses the wheel speed sensor's signals to calculate a vehicle speed and also to determine whether a wheel lock occurs or not.
The HECU monitors the wheel speed sensor's circuit and If it's signal current is continuously out of the specified range, this DTC is set.
The ESC system is the shorten word of Electronic Stability Control system. This system recognizes a critical driving condition by Yaw-rate sensor, Lateral acceleration sensor and Steering angle sensor. And then it stabilizes the vehicle by a individual wheel braking and engine torque control through CAN communication. Among components of this system, the wheel speed sensor(WSS) is the essential component of the brake system. The ESC ECU(HECU, Hydraulic and Electronic Control Unit) uses the wheel speed sensor's signals to calculate a vehicle speed and also to determine whether a wheel lock occurs or not.
The HECU monitors the wheel speed sensor's signal and If its signal is abnormally changed or the signal equivalent to 411 km/h is detected, this DTC is set.
The ESC system is the shorten word of Electronic Stability Control system. This system recognizes a critical driving condition by Yaw-rate sensor, Lateral acceleration sensor and Steering angle sensor. And then it stabilizes the vehicle by a individual wheel braking and engine torque control through CAN communication. Among components of this system, the wheel speed sensor(WSS) is the essential component of the brake system. The ESC ECU(HECU, Hydraulic and Electronic Control Unit) uses the wheel speed sensor's signals to calculate a vehicle speed and also to determine whether a wheel lock occurs or not.
The HECU monitors the wheel speed sensor signal continuously and if the signal of a wheel speed sensor is omitted or too low, this DTC
The pressure sensor is installed in the HECU(Hydraulic and Electronic Control Unit) in the purpose of sensing the driver's braking intention. This sensor has two circuit to measure the current pressure and one circuit to measure the brake oil's temperature. The HECU(Hydraulic and Electronic Control Unit) compares two signals of the pressure sensor and if it differs with normal range, the HECU (Hydraulic and Electronic Control Unit) would judge that the pressure sensor has a fault. The sensor's output is a analog signal to be proportional to the supply voltage. The HECU(Hydraulic and Electronic Control Unit) measures the pressure value by the ratio of signal voltage to supply voltage. In a case of SCC (Smart Cruise Control) system applied, the two more pressure sensors is added to measure the brake oil's pressure of wheel.
The HECU monitors the signal of pressure sensor and if the signal is out of the normal range, this DTC is set.
The pressure sensor is installed in the HECU(Hydraulic and Electronic Control Unit) in the purpose of sensing the driver's braking intention. This sensor has two circuit to measure the current pressure and one circuit to measure the brake oil's temperature. The HECU(Hydraulic and Electronic Control Unit) compares two signals of the pressure sensor and if it differs with normal range, the HECU (Hydraulic and Electronic Control Unit) would judge that the pressure sensor has a fault. The sensor's output is a analog signal to be proportional to the supply voltage. The HECU(Hydraulic and Electronic Control Unit) measures the pressure value by the ratio of signal voltage to supply voltage. In a case of SCC(Smart Cruise Control) system applied, the two more pressure sensors is added to measure the brake oil's pressure of wheel.
The HECU monitors the signal of pressure sensor and if the signal offset of the pressure sensor/the signal noises/the difference between two signals increases above a certain value, this DTC is set.
The Steering Angle Sensor (SAS) uses two sensors (A-sensor and B-sensor) to determine the direction of the rotation of the wheel. The main component of each sensor is LED, photo transistor and slit plate.
The slit plate, which has 45 holes, is installed between LED and photo transistor, and generates signals if the slit plate rotates according to the steering wheel rotation. The steering angle sensor's signals are generated by photo transistor which is driven whenever the light passes through the holes. The HECU receives the steering signals from steering angle sensor by CAN communication and detects the operating speed and the direction of the steering wheel.
The HECU monitors the signal of the steering angle sensor for a normal operation and if it is detected that there is an error in the sensor's status, this DTC is set.
The Steering Angle Sensor (SAS) uses two sensors (A-sensor and B-sensor) to determine the direction of the rotation of the wheel. The main component of each sensor is LED, photo transistor and slit plate.
The slit plate, which has 45 holes, is installed between LED and photo transistor, and generates signals if the slit plate rotates according to the steering wheel rotation. The steering angle sensor's signals are generated by photo transistor which is driven whenever the light passes through the holes. The HECU receives the steering signals from steering angle sensor by CAN communication and detects the operating speed and the direction of the steering wheel.
The steering angle sensor in the ESC system is an absolute angle sensor type. For this reason, the steering angle sensor needs the zero setting(Calibration) by the scantool. If the calibration of this sensor is undone, this DTC is set.
The ESC system is the shorten word of Electronic Stability Control system. This system recognizes a critical driving condition by Yaw-rate sensor, Lateral acceleration sensor and Steering angle sensor. And then it stabilizes the vehicle by a individual wheel braking and engine torque control through CAN communication. Among components of this system, the yaw-rate & lateral G sensor is installed on the lower of the center console. The yaw-rate and the lateral G sensor are installed together in the one container which is called as "Cluster". When the vehicle is moving around a vertical axis, the yaw rate sensor senses the vibration changes of the plate-fork installed in the yaw-rate sensor. When the vehicle's yawing is sensed and the yaw velocity reaches a certain velocity, the ESC control is activated. The lateral G sensor senses a vehicle's lateral acceleration. A small element in the sensor is attached to a deflectable lever-arm. The HECU recognizes a vehicle's direction and a lateral acceleration by the lateral G sensor.
The HECU monitors the signals of the yaw-rate and the lateral G sensor and if its signals are detected out of the normal range, this DTC is set.
The ESC system is the shorten word of Electronic Stability Control system. This system recognizes a critical driving condition by Yaw-rate sensor, Lateral acceleration sensor and Steering angle sensor. And then it stabilizes the vehicle by a individual wheel braking and engine torque control through CAN communication. Among components of this system, the yaw-rate & lateral G sensor is installed on the lower of the center console. The yaw-rate and the lateral G sensor are installed together in the one container which is called as "Cluster". When the vehicle is moving around a vertical axis, the yaw rate sensor senses the vibration changes of the plate-fork installed in the yaw-rate sensor. When the vehicle's yawing is sensed and the yaw velocity reaches a certain velocity, the ESC control is activated. The lateral G sensor senses a vehicle's lateral acceleration. A small element in the sensor is attached to a deflectable lever-arm. The HECU recognizes a vehicle's direction and a lateral acceleration by the lateral G sensor.
The HECU monitors the signals of the yaw-rate and the lateral G sensor and if the abnormal signal is detected or the difference between the acceleration value calculated from the changes of vehicle speed and the acceleration value measured from the sensor is above a certain value, this DTC is set.
A Driver can suspend the ESC function by ESC OFF switch. When this switch signal is delivered into the HECU, the ESC warning lamp is turned on and the ESC control is stopped. When the next switch signal is inputted again, the ESC function is ready. This function is used for sporty driving or vehicle inspection.
The HECU monitors the ESC OFF switch signal and if the ESC OFF switch signal is inputted for more than 1 minute, This DTC is set.
This brake light switch is mounted on the brake-pedal assembly and is used to indicate the status of brake pedal to the HECU. This switch is the normal-open type and is closed when the brake-pedal is pressed. And when the brake-pedal is released, the switch is opened. The HECU uses this as the basic signal to recognize a driver's intention for braking.
The HECU monitors the brake light switch circuit for a normal operation and if it has a open or short circuit, this DTC is set.
The HECU consists of an ECU (Electronic Control Unit) and a HCU(Hydraulic Control Unit). The HCU portion of the assembly contains a pump motor, solenoid valves, and accumulator. Raising and reducing the pressure of brake oil is completed by the electronic motor, according to a measured signal by wheel speed sensor. The function of HCU is to increase, decrease or maintain the hydraulic pressure supplied to a wheel cylinder by operating a return pump according to the control logic when the ESC control is active. The ECU monitors various sensors and switch inputs. These inputs are used to make decisions regarding HCU component operation.
The HECU monitors the operation of the IC components such as memory, register, A/D converter and so on.
If HECU can't write or erase data on the EEPROM or it is detected as an error in RAM etc., this DTC is set.
The HECU sends the request messages, such as torque reduction and fuel cut, to the ECM and TCM through CAN bus line for TCS control. The Engine ECM carries out the fuel-cut logic according to the request messages from the HECU and it also retards an ignition timing by torque reduction requests. The TCM maintains current gear position during TCS control in order to prevent an acceleration force from rising by a kickdown shift.
The HECU monitors CAN messages for a normal operation and if it is detected as a fault in the CAN hardware, this DTC is set.
The HECU sends the request messages, such as torque reduction and fuel cut, to the ECM and TCM through CAN bus line for TCS control. The Engine ECM carries out the fuel-cut logic according to the request messages from the HECU and it also retards an ignition timing by torque reduction requests. The TCM maintains current gear position during TCS control in order to prevent an acceleration force from rising by a kickdown shift.
The HECU checks the CAN communication lines for normal control and if an ECM message is not received for a certain period, this DTC is set.
The HECU sends the request messages, such as torque reduction and fuel cut, to the ECM and TCM through CAN bus line for TCS control. The Engine ECM carries out the fuel-cut logic according to the request messages from the HECU and it also retards an ignition timing by torque reduction requests. The TCM maintains current gear position during TCS control in order to prevent an acceleration force from rising by a kickdown shift.
The HECU checks the CAN communication lines for normal operation and if a TCM message is not received for a certain period, this DTC is set.
The HECU sends the request messages, such as torque reduction and fuel cut, to the ECM and TCM through CAN bus line for TCS control. The Engine ECM carries out the fuel-cut logic according to the request messages from the HECU and it also retards an ignition timing by torque reduction requests. The TCM maintains current gear position during TCS control in order to prevent an acceleration force from rising by a kickdown shift.
The HECU monitors CAN messages for a normal operation and if the abnormal messages from ECM are detected, this DTC is set.
The HECU sends the request messages, such as torque reduction and fuel cut, to the ECM and TCM through CAN bus line for TCS control. The Engine ECM carries out the fuel-cut logic according to the request messages from the HECU and it also retards an ignition timing by torque reduction requests. The TCM maintains current gear position during TCS control in order to prevent an acceleration force from rising by a kickdown shift.
The HECU monitors CAN communication line and if the CAN BUS OFF happens more than 10 times, this DTC is set.
The Steering Angle Sensor(SAS) uses two sensors (A-sensor and B-sensor) to determine the direction of the rotation of the wheel. The main component of each sensor is LED, photo transistor and slit plate.
The slit plate, which has 45 holes, is installed between LED and photo transistor, and generates signals if the slit plate rotates according to the steering wheel rotation. The steering angle sensor's signals are generated by photo transistor which is driven whenever the light passes through the holes. The HECU receives the steering signals from steering angle sensor by CAN communication and detects the operating speed and the direction of the steering wheel.
The HECU checks the CAN communication lines for normal control and if a steering angle sensor's message is not received for a certain period, this DTC is set.
The HECU(Hydraulic and Electronic Control Unit) is one body of the ECU(Electronic Control Unit) and HCU(Hydraulic Control Unit). The HCU consists of an accumulator, a return pump and solenoid valve assay. The increasing, maintaining and decreasing of brake pressure to each wheel cylinder is done by the electronic motor. And the brake pressure in accordance with the control logic is supplied by the pump on the basis of wheel speed sensor's signal.
If the ESC controlling is abnormally being done, this DTC is set.
The ESC system is the shorten word of Electronic Stability Control system. This system recognizes a critical driving condition by Yaw-rate sensor, Lateral acceleration sensor and Steering angle sensor. And then it stabilizes the vehicle by a individual wheel braking and engine torque control through CAN communication. There is no difference in the HECU's hardware side according to a vehicle specification, but there is a difference in the its software side because the applied vehicle parameters differ according to a vehicle specification. The HECU stores the variant code value in the ECU's memory based on the received data by CAN communication.
The HECU checks variant code and if an inappropriate variant code or no variant code is detected, this DTC is set.
The HECU supplies battery power to all solenoid valves with a valve relay which is controlled by the Electronic Control UNIT(ECU).
The valve relay and all solenoid valves are installed inside the HECU (Hydraulic and Electronic Control Unit).
The HECU monitors a voltage of the valve relay for a normal operation and if there is a open or short circuit in the valve relay, this DTC is set.
The BTCS (Brake Traction Control System) is operated when the wheel acceleration and the speed difference exceed the specified value under lower than 50 Km/h(31 MPH). The HECU calculates the wheel disc's temperature logically, which is an assumed value, by using the value of wheel speed, vehicle speed change, control mode and brake light signal. The calculated disc's temperature is used to protect disc from overheating, which is mainly caused by long-time operation.
The HECU calculates a disc's temperature for a normal operation and if the calculated disc's temperature is over 500°C (932°F), this DTC is set.
The HECU(Hydraulic and Electronic Control Unit) is one body of the ECU(Electronic Control Unit) and HCU(Hydraulic Control Unit). The HCU consists of an accumulator, a return pump and solenoid valve assay. The increasing, maintaining and decreasing of brake pressure to each wheel cylinder is done by the electronic motor. And the brake pressure in accordance with the control logic is supplied by the pump on the basis of wheel speed sensor's signal.
The HECU monitors the solenoid valve circuit for a normal operation and if there is a open or short circuit in the valve, this DTC is set.
The HECU(Hydraulic and Electronic Control Unit) is one body of the ECU(Electronic Control Unit) and HCU(Hydraulic Control Unit). The HCU consists of an accumulator, a return pump and solenoid valve assay. The increasing, maintaining and decreasing of brake pressure to each wheel cylinder is done by the electronic motor. And the brake pressure in accordance with the control logic is supplied by the pump on the basis of wheel speed sensor's signal.
The HECU monitors the solenoid valve circuit for a normal operation and if there is a open or short circuit in the valve, this DTC is set.
The HECU(Hydraulic and Electronic Control Unit) is one body of the ECU(Electronic Control Unit) and HCU(Hydraulic Control Unit). The HCU consists of an accumulator, a return pump and solenoid valve assay. The increasing, maintaining and decreasing of brake pressure to each wheel cylinder is done by the electronic motor. And the brake pressure in accordance with the control logic is supplied by the pump on the basis of wheel speed sensor's signal.
The HECU monitors the solenoid valve circuit for a normal operation and if there is a open or short circuit in the valve, this DTC is set.
The HECU(Hydraulic and Electronic Control Unit) is one body of the ECU(Electronic Control Unit) and HCU(Hydraulic Control Unit). The HCU consists of an accumulator, a return pump and solenoid valve assay. The increasing, maintaining and decreasing of brake pressure to each wheel cylinder is done by the electronic motor. And the brake pressure in accordance with the control logic is supplied by the pump on the basis of wheel speed sensor's signal.
The HECU monitors the solenoid valve circuit for a normal operation and if there is a open or short circuit in the valve, this DTC is set.
The HECU(Hydraulic and Electronic Control Unit) is one body of the ECU(Electronic Control Unit) and HCU(Hydraulic Control Unit). The HCU consists of an accumulator, a return pump and solenoid valve assay. The increasing, maintaining and decreasing of brake pressure to each wheel cylinder is done by the electronic motor. And the brake pressure in accordance with the control logic is supplied by the pump on the basis of wheel speed sensor's signal.
The HECU monitors the solenoid valve circuit for a normal operation and if there is a open or short circuit in the valve, this DTC is set.
The HECU(Hydraulic and Electronic Control Unit) is one body of the ECU(Electronic Control Unit) and HCU(Hydraulic Control Unit). The HCU consists of an accumulator, a return pump and solenoid valve assay. The increasing, maintaining and decreasing of brake pressure to each wheel cylinder is done by the electronic motor. And the brake pressure in accordance with the control logic is supplied by the pump on the basis of wheel speed sensor's signal.
The HECU monitors the solenoid valve circuit for a normal operation and if there is a open or short circuit in the valve, this DTC is set.
The HECU(Hydraulic and Electronic Control Unit) is one body of the ECU(Electronic Control Unit) and HCU(Hydraulic Control Unit). The HCU consists of an accumulator, a return pump and solenoid valve assay. The increasing, maintaining and decreasing of brake pressure to each wheel cylinder is done by the electronic motor. And the brake pressure in accordance with the control logic is supplied by the pump on the basis of wheel speed sensor's signal.
The HECU monitors the solenoid valve circuit for a normal operation and if there is a open or short circuit in the valve, this DTC is set.
The HECU(Hydraulic and Electronic Control Unit) is one body of the ECU(Electronic Control Unit) and HCU(Hydraulic Control Unit). The HCU consists of an accumulator, a return pump and solenoid valve assay. The increasing, maintaining and decreasing of brake pressure to each wheel cylinder is done by the electronic motor. And the brake pressure in accordance with the control logic is supplied by the pump on the basis of wheel speed sensor's signal.
The HECU monitors the solenoid valve circuit for a normal operation and if there is a open or short circuit in the valve, this DTC is set.
The HECU(Hydraulic and Electronic Control Unit) is one body of the ECU(Electronic Control Unit) and HCU(Hydraulic Control Unit). The HCU consists of an accumulator, a return pump and solenoid valve assay. The increasing, maintaining and decreasing of brake pressure to each wheel cylinder is done by the electronic motor.
And the brake pressure in accordance with the control logic is supplied by the pump on the basis of wheel speed sensor's signal.
The HECU monitors the solenoid valve circuit for a normal operation and if there is a open or short circuit in the valve, this DTC is set.
The HECU(Hydraulic and Electronic Control Unit) is one body of the ECU(Electronic Control Unit) and HCU(Hydraulic Control Unit). The HCU consists of an accumulator, a return pump and solenoid valve assay. The increasing, maintaining and decreasing of brake pressure to each wheel cylinder is done by the electronic motor.
And the brake pressure in accordance with the control logic is supplied by the pump on the basis of wheel speed sensor's signal.
The HECU monitors the solenoid valve circuit for a normal operation and if there is a open or short circuit in the valve, this DTC is set.
The HECU(Hydraulic and Electronic Control Unit) is one body of the ECU(Electronic Control Unit) and HCU(Hydraulic Control Unit). The HCU consists of an accumulator, a return pump and solenoid valve assay. The increasing, maintaining and decreasing of brake pressure to each wheel cylinder is done by the electronic motor.
And the brake pressure in accordance with the control logic is supplied by the pump on the basis of wheel speed sensor's signal.
The HECU monitors the solenoid valve circuit for a normal operation and if there is a open or short circuit in the valve, this DTC is set.
The HECU(Hydraulic and Electronic Control Unit) is one body of the ECU(Electronic Control Unit) and HCU(Hydraulic Control Unit). The HCU consists of an accumulator, a return pump and solenoid valve assay. The increasing, maintaining and decreasing of brake pressure to each wheel cylinder is done by the electronic motor.
And the brake pressure in accordance with the control logic is supplied by the pump on the basis of wheel speed sensor's signal.
The HECU monitors the solenoid valve circuit for a normal operation and if there is a open or short circuit in the valve, this DTC is set.
The HECU(Hydraulic and Electronic Control Unit) is one body of the ECU(Electronic Control Unit) and HCU(Hydraulic Control Unit). The HCU consists of an accumulator, a return pump and solenoid valve assay. The increasing, maintaining and decreasing of brake pressure to each wheel cylinder is done by the electronic motor.
And the brake pressure in accordance with the control logic is supplied by the pump on the basis of wheel speed sensor's signal.
The HECU monitors the solenoid valve circuit for a normal operation and if there is a open or short circuit in the valve, this DTC is set.
The HECU supplies battery power to the electric motor through the motor relay which is controlled by the Electronic Control Unit(ECU). The electric motor pump supplies hydraulic pressure to all wheel brake calipers by operating the piston inside the pump.
The HECU monitors the pump motor circuit and if it is detected as an open/short circuit, fuse open, or motor lock, this DTC is set.
Description
The ESC system is the shorten word of Electronic Stability Control system. This system recognizes a critical driving condition by Yaw-rate sensor, Lateral acceleration sensor and Steering angle sensor. And then it stabilizes the vehicle by a individual wheel braking and engine torque control through CAN communication. Among components of this system, the yaw-rate & lateral G sensor is installed on the lower of the center console. The yaw-rate and lateral G sensor are installed together in the one container which is called as " Sensor cluster". When the vehicle is moving around a vertical axis, the yaw rate sensor senses the vibration changes of the plate-fork installed in the yaw-rate sensor. When the vehicle's yawing is sensed and the yaw velocity reaches a certain velocity, the ESC control is activated. The lateral G sensor senses a vehicle's lateral acceleration. A small element in the sensor is attached to a deflectable lever-arm. The HECU recognizes a vehicle's direction and a lateral acceleration by the lateral G sensor.
Scheme 23
- The ESC OFF switch is for the user to turn off the ESC system.
- The ESC OFF lamp is on when ESC OFF switch is engaged.
Scheme 24
- Turn ignition switch OFF and disconnect the negative (-) battery cable
- Remove the crash pad side cover. (Refer to the «CRASH PAD»(ref-345931-S27758735332009102300000) )
- Remove the lower panel. (Refer to the «CRASH PAD»(ref-345931-S27758735332009102300000) )
- Remove the lower crash pad switch assembly by using the scraper and then disconnect the connectors.
- Check the continuity between the switch terminals as the ESC OFF switch is engaged.
Scheme 25
Steering Wheel Angle Sensor detects rotating direction of the vehicle. Rotating direction detected by the sensor is communicated with HECU as CAN signal involving information about the angle through CAN communication line.
HECU detects speed of the steering wheel handling and the angle with this CAN signal. HECU also uses this signal as the input signal to control anti-roll.
