DTC C1604 Ecu Hardware Error: General Description
WARNING: This page is about a different car, the 2007 Kia Sedona and 2006 Kia Sedona. However, it is still accessible from the selected car via links, so may be relevant.
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 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 brake caliper by operating return pump according to HECU control signal while ABS control is active.