Kia 2004.5 Spectra Service Technical Training page 180

2004.5 Spectra Technology
The diagram shows the hydraulic circuit of the HECU.
Because Spectra's ABS is a 4-channel system, there is
one inlet and dump valve for each wheel caliper. The
inlet or isolation solenoid valve is a NO (normally
open) valve that connects or isolates (blocks) the
hydraulic path between master cylinder and the wheel
caliper. The dump valve is a NC (normally closed)
valve until the ABSCM allows the hydraulic pressure in
that channel to go down (decrease).
The ABS tests itself every time the vehicle is started
and every time the brakes are applied by evaluating its
own signals. If a defect is detected, the system turns
off and turns on the ABS lamp, while leaving normal
braking unaffected.
Brakes
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