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.
Under normal conditions, the inlet valves of all four wheels are not closed during control for longer than 1.28s or If the controller requests pressure-hold or pressure-decrease for longer than 1.28s, a fault is detected. The ABS/ESP warning lamp is turned ON and the EBD warning lamp is turned OFF.
Item | Detecting Condition | Possible cause | |
DTC Strategy | ● Signal monitoring | ● Inoperative HECU | |
Case 1 | Monitoring Period | ● Continuous | |
Enable Conditions | ● If the controller requests pressure-hold or pressure-decrease for longer than 1.28 s, a fault is stored. | ||
Case 2 | Monitoring Period | ● Continuous (at vehicle reference speed ＞ 6 m/s, no detected under voltage and a fault is not already detected) | |
Enable Conditions | ● The monitoring reports a failure if continuous ESP control occurs for a time period ＞= 10 s. | ||
Fail Safe | ● The ABS/ESP functions are inhibited, allow the EBD control. ● The ABS/ESP warning lamps are activated. | ||
Ignition "OFF".
Ignition "ON".
Connect scantool and select "Diagnostic Trouble Codes (DTCs)" mode.
Using a scantool, Clear DTC.
Select "Diagnostic Trouble Codes(DTCs)" mode again.
Are any DTCs present ?
▶ 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 faulty HECU or was repaired and HECU memory was not cleared. go to "Verification Of Vehicle Repair" 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.
