C1604

C1604

Component Location:

General Description
The HECU is composed of a 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 operated 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 hydraulic pressure supplied to a wheel cylinder by operating return pump according to HECU control signal while ABS control.

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 written, or when the master/slave processor detects abnormal operation in RAM, Status Register, Interrupt, Timer, A/D converter or cycle time.

DTC Detecting Condition:

Component Inspection
1. Ignition "OFF".
2. Engine "ON".
3. Does warning lamp remain On?

YES - 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.

NO - Fault is intermittent caused by faulty HECU or was repaired and HECU memory was not cleared, go to "Verification of Vehicle Repair" procedure.

Verification of Vehicle Repair
After a repair, it is essential to verify that the fault has been corrected.
1. Connect scantool and select "Diagnostic Trouble Codes (DTCs)" mode
2. Using a scantool, Clear DTC.
3. Operate the vehicle within DTC Detecting Condition in General Information.
4. Are any DTCs present?

YES - Go to the applicable troubleshooting procedure.

NO - System performing to specification at this time.