The one pressure sensor ,installed in the master cyclinder, sense the brake oil pressure to judge driver’s brake intention when ESC is operating. There are movable and unmovable ceramic disk in pressure sensor. when the pressure is applied to the disk, the distance between the disks changes. Therefore the distance between the disks changs linearly when the pressure is applied to the movable disk by break opreation . Max. measurable pressure is 170bar. 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, or In spite of no brake switch signal, master cyclinder pressure exceeds 20bar when brake switch is normal.
Item | Detecting Condition | Possible Cause |
DTC Strategy | ● Voltage Monitoring | ● Open or short of pressure sensor circuit ● Faulty pressure sensor ● Faulty HECU |
Detect Mode | ● Outside the ABS control cycle ● Diagnosis mode ● Failure mode | |
Enable Conditions | ● If input signal is noisy, Which the gradient of the sensor signal is larger than 15bar over 25times in 2sec, ECU detect the failure. ● Outside an ABS/TCS/ESP control,And afrer normal operation of BLS, If the pressure sensor signal is higher than 20bar and BLS is low for 3sec, ECU detect the failure. | |
Fail Safe | ● Inhibit the ESP control and allow the ABS/EBD/TCS control. Meanwhile, stop checking the ESP switch failure under the ESP control. ● The ESP warning lamps are activated. |
