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 cyclinder is applied to pressure sensor, the strain of the piezo element is changed and then the resistance of brige circuit is chanded according to changed strain.
Therefore this changed resistance changes output voltage of brige 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.
With the driver torque demand and the lateral acceleration a driver braking demand is calculated. Unless the pump motor is opreating or there is a brake signal, The offset compensation is executed.
A failure is detected if offset value exceeded ±15 bar.
Item | Detecting Condition | Possible cause |
DTC Strategy | ● Voltage Monitoring | ● Open or short of pressure sensor circuit ● Faulty pressure sensor ● Faulty HECU |
Monitoring Period | ● After Pressure sensor initialization. ● No under voltage ● No pumps are running. ● No BLS-signal is set. | |
Enable Conditions | ● The pressure sensor-offset value must be in the range of ± 15 bar. A failure is detected if this range is exceeded. | |
Fail Safe | ● Reduced function caused by faulty pressure sensor signal. ● Sensor failure outside the ABS control cycle - Only the ABS/ESP functions are inhibited, allow the EBD. The ABS/ESP warning lamps are activated and the EBD warning lamp is not activated. ● Sensor failure inside the ABS control cycle - Inhibit the ESP control, allow the EBD. The ESP warning lamps are activated. After the control, the ABS functions are inhibited. The ABS warning lamps are activated. |
