The pressure sensor, installed in the HECU, senses the brake oil pressure to judge a driver's brake intention when the ESP program is operated. If pressure of master cyclinder is applied to pressure sensor, the strain of the piezo element is changed and then the resistance of bridge circuit is changed according to the changed strain. Therefore this changed resistance changes the output voltage of bridge circuit and the output voltage changes linearly. The sensor output is an analog signal in proportion to the 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.
Item | Detecting Condition | Possible cause | |
DTC Strategy |
•
Voltage Monitoring | 1. Open or short of pressure sensor circuit 2. Faulty pressure sensor 3. Faulty HECU | |
Case 1 | MonitoringPeriod |
•
Continuous | |
Enable Conditions |
•
A sensor supply failure is detected if Sensor Supply Voltage shows under 4.75V or over 5.25V for 60ms. | ||
Case 2 | MonitoringPeriod |
•
Continuous | |
Enable Conditions |
•
A Fault is set if the sensor values(PRS1,PRS2) keep under 0.6V or over 4.5V for 100ms. - PRS1 : Sensor output 1 - PRS2 : Sensor output 2(Inverse image of PRS1) | ||
Case 3 | MonitoringPeriod |
•
Continuous | |
Enable Conditions |
•
A Fault is set if the if sum of the sensor values(PRS1+PRS2) keep under 4.4V or over 5.4V. - PRS1 : Sensor output 1 - PRS2 : Sensor output 2(Inverse image of PRS1) | ||
Fail Safe |
•
The ABS/ESP functions are inhibited.
•
The ABS/ESP warning lamps are activated. | ||
