4.
Monitor the "Pressure sensor" parameter on the Scantool.
Specification : Approx. 60 bar ~150 bar (There are difference in displayed parameter according to braking force)
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 linerly. 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 |
Connect scantool to Data Link Connector(DLC).
Ignition "ON" ＆ Engine "ON".
Press the brake pedal.
Monitor the "Pressure sensor" parameter on the Scantool.
Specification : Approx. 60 bar ~150 bar (There are difference in displayed parameter according to braking force)
Whenever brake pedal is pushed down, is the pressure sensor's scantool data changed?
▶ Fault is caused by having been repaired and HECU memory was not cleared. Clear the DTC and then go to "Verification of Vehicle Repair" procedure.
▶ Go to "Component Inspection" procedure.
Ignition "OFF".
Engine "ON".
Does warning lamp remain On?
▶ Substitute with a known-good HECU and check for proper operation. If problem is corrected, replace HECU and then go to "Verification of Vehicle Repair" procedure.
▶ Fault is intermittent caused by open or short of wheel speed sensor harness, faulty wheel speed sensor. Go to the applicable troubleshooting procedure.
After a repair, it is essential to verify that the fault has been corrected.
Connect scantool and select "Diagnostic Trouble Codes(DTCs)" mode
Using a scantool, Clear DTC.
Operate the vehicle within DTC Detecting Condition in General Information.
Are any DTCs present ?
▶ Go to the applicable troubleshooting procedure.
▶ System performing to specification at this time.
