Component Location
General Description
The HECU is composed of an ECU (Electronic Control Unit ) and a HCU( Hydraulic Control Unit) , HCU is composed of a source of hydraulic pressure and modulator valve block.
Increase and decrease of hydraulic pressure is opreated by electronic motor, According to a detected signal by wheel speed sensor.
The hydraulic pressure which is needed for control is supplied by pump.
The HCU’ function which is composed of a accumulator, return pump, solenoid valve is to increase, decrease or maintain the hydralic pressure supplied to a wheel cylinder by operating return pump according to HECU control signal while ABS control is active.
DTC Description
The HECU monitors the operation of the IC components such as memory, register, A/D converter and so on.
The ECU sets this code when the EEPROM data read by the master processor is different than prior data writed, or when the master/slave processor detects abnormal operation in RAM, Status Register, Interrupt, Timer, A/D converter or cycle time.
DTC Detecting Condition
Item | Detecting Condition | Possible cause |
DTC Strategy | ? Internal monitoring | ? Faulty HECU |
Case 1 | Monitoring Period | ? Continuous |
Enable Conditions | ? If Internal control unit failures of the master/slave processor or peripheral integrated circuits is detected. |
Case 2 | Monitoring Period | ? Directly after ignition on, during reading of EEPROM-values |
Enable Conditions | ? Failure is set if checksum not correct or PSW-EEPROM-Handler reported unknown failure during EEPROM-value reading. ? If EEPROM reading sequence take longer then 3s, a failure is set. |
Fail Safe | ? The ABS/EBD/ESP functions are inhibited. ? The ABS/EBD/ESP warning lamps are activated. |