C1604

DTC C1604





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 a pump. The HCU function which is composed of an 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, ND 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, ND 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 the applicable troubleshooting 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.