General Description
The ABS ECU (Electronic Control Unit) checks the battery voltage and alternator output voltage to determine, as a safety issue, whether the ABS system can operate normally or not.
The normal battery voltage range is essential for controlling the ABS system as intended.
DTC Description
The ABS ECU monitors battery voltage and alternator output voltage.
When the voltage is higher than the expected normal value, this code is set, and the ABS/EBD/ESC functions are prohibited.
If the voltage recovers, to within normal operating ranges, then the controller returns to normal operation as well.
The ABS ECU (Electronic Control Unit) checks the battery voltage and alternator output voltage to determine, as a safety issue, whether the ABS system can operate normally or not.
The normal battery voltage range is essential for controlling the ABS system as intended.
The ABS ECU monitors the battery voltage and alternator output voltage by reading the value of voltage.
When the voltage is lower than the expected normal value, this code is set.
The ABS/ESC functions are prohibited and the EBD function is allowed on LOW VOLTAGE CONDITION, the ABS/EBD/ESC functions are prohibited on UNDER VOLTAGE CONDITION.
If the voltage recovers, to within normal operating ranges, then the controller returns to normal operations as well.
The HECU monitors supply voltage of each sensor for normal ESC control.
If supply voltage is out of specified range ABS/ESC warning lamps are turned on and ABS/ESC controls are inhibited.
A failure is detected if the external sensor supply voltage is out of the specified range for more than the specified min. fault duration.
The wheel speed sensor is the essential component the ABS ECU uses to calculate vehicle speed and to determine whether wheel lock occurs.
For example, rear wheel speed signal is used as a reference value, for vehicle speed, in front wheel drive vehicles, and if a difference between front and rear wheel speed occurs, then ABS control is performed.
Wheel speed sensor is active hall-sensor type.
The ABS ECU monitors the wheel speed sensor circuit continuously.
If the sensor signal current is continuously out of the specified range for 140msec, then the HECU determines that the circuit is open/short, and sets this code.
Warning lamp is turned OFF unless additional faults are detected when the IG KEY is turned ON again, and wheel speed is more than 10 km/h.
The wheel speed sensor is the essential component the ABS ECU uses to calculate vehicle speed and to determine whether wheel lock occurs.
For example, rear wheel speed signal is used as a reference value, for vehicle speed, in front wheel drive vehicles, and if a difference between front and rear wheel speed occurs, then ABS control is performed.
Wheel speed sensor is active hall-sensor type.
The ABS ECU monitors the wheel speed sensor signal continuously.
This code is set if an abnormal speed change ratio is detected while the vehicle speed is more than 2 km/h.
Warning lamp is turned OFF unless additional faults are detected when the IG KEY is turned ON again, and wheel speed is more than 10 km/h.
The wheel speed sensor is the essential component the ABS ECU uses to calculate vehicle speed and to determine whether wheel lock occurs.
For example, rear wheel speed signal is used as a reference value, for vehicle speed, in front wheel drive vehicles, and if a difference between front and rear wheel speed occurs, then ABS control is performed.
Wheel speed sensor is active hall-sensor type.
The ABS ECU monitors the wheel speed sensor signal continuously.
This code is set when the sensor air gap is out of specified range or when the ABS control cycle is continued abnormally.
The HECU checks for air gap malfunctioning by monitoring the sensor signal at speeds between 2 km/h to 10 km/h.
Warning lamp is turned OFF unless additional faults are detected when the IG KEY is turned ON again, and wheel speed is more than 10 km/h (6.2 mph).
The wheel speed sensor is the essential component the ABS ECU uses to calculate vehicle speed and to determine whether wheel lock occurs.
For example, rear wheel speed signal is used as a reference value, for vehicle speed, in front wheel drive vehicles, and if a difference between front and rear wheel speed occurs, then ABS control is performed.
Wheel speed sensor is active hall-sensor type.
The ABS ECU monitors the wheel speed sensor circuit continuously.
If the sensor signal current is continuously out of the specified range for 140msec, then the HECU determines that the circuit is open/short, and sets this code.
Warning lamp is turned OFF unless additional faults are detected when the IG KEY is turned ON again, and wheel speed is more than 10 km/h.
The wheel speed sensor is the essential component the ABS ECU uses to calculate vehicle speed and to determine whether wheel lock occurs.
For example, rear wheel speed signal is used as a reference value, for vehicle speed, in front wheel drive vehicles, and if a difference between front and rear wheel speed occurs, then ABS control is performed.
Wheel speed sensor is active hall-sensor type.
The ABS ECU monitors the wheel speed sensor circuit continuously.
If the sensor signal current is continuously out of the specified range for 140msec, then the HECU determines that the circuit is open/short, and sets this code.
Warning lamp is turned OFF unless additional faults are detected when the IG KEY is turned ON again, and wheel speed is more than 10 km/h (6.2 mph).
The wheel speed sensor is the essential component the ABS ECU uses to calculate vehicle speed and to determine whether wheel lock occurs.
For example, rear wheel speed signal is used as a reference value, for vehicle speed, in front wheel drive vehicles, and if a difference between front and rear wheel speed occurs, then ABS control is performed.
Wheel speed sensor is active hall-sensor type.
The ABS ECU monitors the wheel speed sensor signal continuously.
This code is set if an abnormal speed change ratio is detected while the vehicle speed is more than 2 km/h.
Warning lamp is turned OFF unless additional faults are detected when the IG KEY is turned ON again, and wheel speed is more than 10 km/h.
The wheel speed sensor is the essential component the ABS ECU uses to calculate vehicle speed and to determine whether wheel lock occurs.
For example, rear wheel speed signal is used as a reference value, for vehicle speed, in front wheel drive vehicles, and if a difference between front and rear wheel speed occurs, then ABS control is performed.
Wheel speed sensor is active hall-sensor type.
The ABS ECU monitors the wheel speed sensor signal continuously.
This code is set when the sensor air gap is out of specified range or when the ABS control cycle is continued abnormally. The HECU checks for air gap malfunctioning by monitoring the sensor signal at speeds between 2 km/h to 10 km/h.
Warning lamp is turned OFF unless additional faults are detected when the IG KEY is turned ON again, and wheel speed is more than 10 km/h (6.2 mph).
The wheel speed sensor is the essential component the ABS ECU uses to calculate vehicle speed and to determine whether wheel lock occurs.
For example, rear wheel speed signal is used as a reference value, for vehicle speed, in front wheel drive vehicles, and if a difference between front and rear wheel speed occurs, then ABS control is performed.
Wheel speed sensor is active hall-sensor type.
The ABS ECU monitors the wheel speed sensor circuit continuously.
If the sensor signal current is continuously out of the specified range for 140msec, then the HECU determines that the circuit is open/short, and sets this code.
Warning lamp is turned OFF unless additional faults are detected when the IG KEY is turned ON again, and wheel speed is more than 10 km/h.
The wheel speed sensor is the essential component the ABS ECU uses to calculate vehicle speed and to determine whether wheel lock occurs.
For example, rear wheel speed signal is used as a reference value, for vehicle speed, in front wheel drive vehicles, and if a difference between front and rear wheel speed occurs, then ABS control is performed.
Wheel speed sensor is active hall-sensor type.
The ABS ECU monitors the wheel speed sensor signal continuously.
This code is set if an abnormal speed change ratio is detected while the vehicle speed is more than 2 km/h. Warning lamp is turned OFF unless additional faults are detected when the IG KEY is turned ON again, and wheel speed is more than 10 km/h.
The wheel speed sensor is the essential component the ABS ECU uses to calculate vehicle speed and to determine whether wheel lock occurs.
For example, rear wheel speed signal is used as a reference value, for vehicle speed, in front wheel drive vehicles, and if a difference between front and rear wheel speed occurs, then ABS control is performed.
Wheel speed sensor is active hall-sensor type.
The ABS ECU monitors the wheel speed sensor signal continuously.
This code is set when the sensor air gap is out of specified range or when the ABS control cycle is continued abnormally. The HECU checks for air gap malfunctioning by monitoring the sensor signal at speeds between 2 km/h to 10 km/h.
Warning lamp is turned OFF unless additional faults are detected when the IG KEY is turned ON again, and wheel speed is more than 10 km/h (6.2 mph).
The wheel speed sensor is the essential component the ABS ECU uses to calculate vehicle speed and to determine whether wheel lock occurs.
For example, rear wheel speed signal is used as a reference value, for vehicle speed, in front wheel drive vehicles, and if a difference between front and rear wheel speed occurs, then ABS control is performed.
Wheel speed sensor is active hall-sensor type.
The ABS ECU monitors the wheel speed sensor signal continuously.
This code is set if an abnormal speed change ratio is detected while the vehicle speed is more than 2 km/h.
Warning lamp is turned OFF unless additional faults are detected when the IG KEY is turned ON again, and wheel speed is more than 10 km/h.
The wheel speed sensor is the essential component the ABS ECU uses to calculate vehicle speed and to determine whether wheel lock occurs.
For example, rear wheel speed signal is used as a reference value, for vehicle speed, in front wheel drive vehicles, and if a difference between front and rear wheel speed occurs, then ABS control is performed.
Wheel speed sensor is active hall-sensor type.
The ABS ECU monitors the wheel speed sensor signal continuously.
This code is set when the sensor air gap is out of specified range or when the ABS control cycle is continued abnormally.
The HECU checks for air gap malfunctioning by monitoring the sensor signal at speeds between 2 km/h to 10 km/h.
Warning lamp is turned OFF unless additional faults are detected when the IG KEY is turned ON again, and wheel speed is more than 10 km/h (6.2 mph).
The pressure sensor, installed in the HECU, sense the brake oil pressure to judge driver's brake intention when ESP is operating.
If pressure of master cylinder is applied to pressure sensor, the strain of the piezo element is changed and then the resistance of bridge circuit is changed according to changed strain.
Therefore this changed resistance changes output voltage of bridge circuit and output voltage changes linearly.
The sensor output is a analog signal in proportion to supply voltage, and the HECU recognizes a pressure value according to signal ratio about supply voltage.
A failure is detected if the output signal voltage of the pressure sensor is out of specified range.
The pressure sensor, installed in the HECU, sense the brake oil pressure to judge driver's brake intention when ESC is operating.
If pressure of master cylinder is applied to pressure sensor, the strain of the piezo element is changed and then the resistance of bridge circuit is changed according to changed strain.
Therefore this changed resistance changes output voltage of bridge circuit and output voltage changes linearly.
The sensor output is a analog signal in proportion to supply voltage, and the HECU recognizes a pressure value according to signal ratio about supply voltage.
The failure is detected if the pressure sensor signal noise is out of normal range, or the pressure sensor signal is changed abnormally.
In spite of no brake switch signal, master cylinder pressure exceeds 20bar when brake switch is normal.
The Steering wheel angle sensor uses two sensors (A-sensor and B-sensor) to determine the direction of the rotation.
The main components of each sensor are LED, photo transistor and slit plate.
The slit plate, which has 45 holes, is installed between LED and photo transistor, and generates signals if slit plate rotates according to the steering wheel rotation.
The sensor signals are generated by photo transistor which is driven whenever the light passes through the holes. The HECU detects operating speed and direction of the steering wheel by this input signal, and the signal is used to input signal for anti-roll control.
If some signal voltage stays in abnormal voltage range, the time is counted separately.
And if the monitored time exceeds the specified min. fault duration, failure is detected.
The monitoring starts 1sec after Power Up.
The Steering wheel angle sensor uses two sensors (A-sensor and B-sensor) to determine the direction of the rotation. The main components of each sensor are LED, photo transistor and slit plate.
The slit plate, which has 45 holes, is installed between LED and photo transistor, and generates signals if slit plate rotates according to the steering wheel rotation.
The sensor signals are generated by photo transistor which is driven whenever the light passes through the holes. The HECU detects operating speed and direction of the steering wheel by this input signal, and the signal is used to input signal for anti-roll control.
This monitoring function monitors the changing point of N-signal with measured steering angle from ST1 and ST2.
If N-signal changing point differs more than predefined degree, the failure is detected.
If there is no variation of the steering wheel angle for predefined time ECU detect the failure.
When the vehicle is turning with respect to a vertical axis, the yaw rate sensor detects the yaw rate electronically by the vibration change of plate fork inside the yaw rate sensor.
If yaw velocity reaches the specific velocity after it detects the vehicle' yawing, the ESC control is reactivated.
The lateral G sensor senses vehicle's lateral G. A small element inside the sensor is attached to a deflectable lever arm by lateral G.
Direction and magnitude of lateral G loaded to vehicle can be known with electrostatic capacity changing according to lateral G.
A failure is detected if the Yaw rate & lateral G sensor's message was not received or HECU detects CAN Bus off state for more than the specified failure detection time.
When the vehicle is turning with respect to a vertical axis, the yaw rate sensor detects the yaw rate electronically by the vibration change of plate fork inside the yaw rate sensor.
If yaw velocity reaches the specific velocity after it detects the vehicle' yawing, the ESC control is reactivated.
The lateral G sensor senses vehicle's lateral G. A small element inside the sensor is attached to a deflectable lever arm by lateral G.
Direction and magnitude of lateral G loaded to vehicle can be known with electrostatic capacity changing according to lateral G.
If the difference between estimated value and measured value of the sensor is larger than predefined value for predefined time, the failure is recognized.
Driver can inhibit the ESC control by ESC switch.
When switch signal send into HECU, ESC warning lamp go ON and ESC control is stopped and if next switch signal is inputted again, ESC control is ready. This function is used for sporty driving or vehicle inspection.
Trouble code is set when the condition that the level of ESC switch is high is continued for 60sec.
When the ESC switch failure is set, Warning lamps won't illuminate and HECU allow the ABS/EBD/ESC control.
This switch is mounted on the pedal assembly and is used to indicate brake pedal status to the HECU. The switch is turned on when brake is pressed.
The brake light switch is a normally-open contact which runs to battery voltage when active (brake pressed).
When passive (brake released), the cable is grounded via the brake light bulbs.
The brake light signal is a reference to judge driver's intention for braking.
The HECU checks open or short circuit of brake light switch for normal ESC control.
If an error is present, the warning lamp will illuminate.
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.
Increase and decrease of hydraulic pressure is operated by 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 return pump according to HECU control signal while ABS control is active.
The ECU monitors various sensor 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.
The ECU sets this code when the EEPROM data read by the master processor is different than prior data written, or when the master/slave processor detects abnormal operation in RAM, Status Register, Interrupt, Timer, A/D converter or cycle time.
The HECU send requirement data, such as Torque reduction, the number of fuel cut cylinders, and ESC control requests, to the Engine PCM (ECM & TCM) through CAN bus line.
The Engine PCM (ECM) performs fuel cut functions according to requests from the HECU and retards ignition timing by torque reduction requests.
The PCM (TCM) maintains current gear positions during ESC control time, in order not to increase power which causes a Kickdown shift.
The HECU checks the CAN RAM for normal TCS control, and sets this code if a CAN RAM malfunction is detected.
The HECU send requirement data, such as Torque reduction, the number of fuel cut cylinders, and ESC control requests, to the Engine PCM (ECM & TCM) through CAN bus line.
The Engine PCM (ECM) performs fuel cut functions according to requests from the HECU and retards ignition timing by torque reduction requests.
The PCM (TCM) maintains current gear positions during ESC control time, in order not to increase power which causes a Kickdown shift.
The HECU checks the CAN communication lines for normal ESC control, and sets this code if an ECM message is not received within 500ms.
The HECU does not detect this code until 2 seconds after the IG KEY is turned to ON.
The HECU send requirement data, such as Torque reduction, the number of fuel cut cylinders, and ESC control requests, to the Engine PCM (ECM & TCM) through CAN bus line.
The Engine PCM (ECM) performs fuel cut functions according to requests from the HECU and retards ignition timing by torque reduction requests.
The PCM (TCM) maintains current gear positions during ESC control time, in order not to increase power which causes a Kickdown shift.
The HECU checks the CAN communication lines for normal ESC control, and sets this code if an TCM message is not received within 500ms.
The HECU does not detect this code until 2 seconds after the IG KEY is turned to ON.
The HECU send requirement data, such as Torque reduction, the number of fuel cut cylinders, and ESC control requests, to the Engine PCM (ECM & TCM) through CAN bus line.
The Engine PCM (ECM) performs fuel cut functions according to requests from the HECU and retards ignition timing by torque reduction requests.
The PCM (TCM) maintains current gear positions during ESC control time, in order not to increase power which causes a Kickdown shift.
The HECU checks the CAN communication lines for normal ESC control, and sets this code if the data received between the EMS2 and TCM is not the same.
The HECU will not detect this code until 2 seconds after the IG KEY is turned ON.
The HECU send requirement data, such as Torque reduction, the number of fuel cut cylinders, and ESC control requests, to the Engine PCM (ECM & TCM) through CAN bus line.
The Engine PCM (ECM) performs fuel cut functions according to requests from the HECU and retards ignition timing by torque reduction requests.
The PCM (TCM) maintains current gear positions during ESC control time, in order not to increase power which causes a Kickdown shift.
The HECU checks the CAN communication lines for normal TCS control, and sets this code if CAN BUS OFF status is detected for more than 100ms.
When the vehicle is turning with respect to a vertical axis, the yaw rate sensor detects the yaw rate electronically by the vibration change of plate fork inside the yaw rate sensor.
If yaw velocity reaches the specific velocity after it detects the vehicle' yawing, the ESC control is reactivated.
The lateral G sensor senses vehicle's lateral G. A small element inside the sensor is attached to a deflectable lever arm by lateral G.
Direction and magnitude of lateral G loaded to vehicle can be known with electrostatic capacity changing according to lateral G.
The HECU checks the sensor CAN H/W for normal ESC control, and sets this code if a sensor CAN H/W malfunction is detected.
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).
ABS ECU monitors voltage of the valve relay to check if ABS ECU can perform ABS control normally.
When the valve relay is switched to ON, the HECU will set this code if the solenoid drive voltage is below permissible voltage ranges for a period of time.
When the valve relay is switched to OFF, the HECU sets this code if the solenoid drive voltage is over the permissible voltage range for a period of time.
BTCS (Brake Traction Control System) is operated when the value (Wheel acceleration value + speed difference value) exceeds the specified value when vehicle speed is lower than the 50 km/h.
The BTCS installed HECU calculates the DISC temperature logically, which is an assumed value, by using the value of Wheel speed, vehicle speed change, CONTROL MODE and BLS SIGNAL.
Assumed DISC Temperature is used to protect DISC overheating, caused by long-time operation, which may cause a decrease in brake efficiency.
If the HECU decides that the Disc is overheated (above 500°C), then it turns the ESC lamp ON and inhibits BTCS operation to protect overheating of the disc.
If the calculated temperature becomes lower than specified value (aprox. 300°C), then the HECU turns the ESC lamp OFF and operates the BTCS again.
The ABS HECU is composed of a ECU (Electronic Control Unit) and an HCU (Hydraulic Control Unit), so the HECU hardware includes all solenoid valves inside the unit as well as the ECU.
Solenoid valves are switched to ON, OFF by HECU when the ABS is activated. Solenoid valves function is to increase, decrease or maintain the hydraulic pressure supplied to a wheel cylinder.
The HECU monitors the operation of the valves by checking the drive circuit of the solenoid valves, and then sets this code when the unexpected drive voltage is detected.
For example, the HECU sets the DTC if an unexpected high drive voltage is detected when the valve relay is switched to OFF. (or unexpected low voltage is detected when the solenoid valve drive TR is switched to ON)
The ABS ECU supplies battery power to the electric motor by way of a 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.