Kia Carens. Manual - part 222

For vehicles with ABS, the following symptoms can occur, but indicate normal operation of the ABS.

Symptom

Descriptions

Motor noise

Noise can be heard when ABS hydraulic unit is operated.

Noise from suspension system

Since braking is done in 3 steps during operation of ABS, noise from suspension
system can be heard.

Oscillation of brake pedal

Slight oscillation (kickback) on brake pedal occurs during operation of ABS.

Principle of operation

Standard braking (Non-ABS braking)

When the brake pedal is depressed, the power brake unit closes the central valve of the master cylinder and generates
pressure on the brake hydraulic pressure line. This opens the solenoid inlet valve and closes the outlet valve and
transmits hydraulic pressure from the master cylinder to the wheel cylinders.

ABS braking (2.1 Maintaining pressure)

After the ABS control unit detects wheel lock due to excessively increased pressure, the ABS control unit closes the inlet
valve to avoid further increase in hydraulic pressure.

ABS braking (2.2 Decreasing pressure)

If lock wheel continues, the ABS control unit opens the corresponding outlet valve so that brake fluids flow to the
pressure accumulator. This reduces pressure only for wheels that are locked.

ABS braking (2.3 Increasing pressure)