Skoda Felicia

Since 1994 of release

Repair and car operation

System of antiblocking of brakes (ABS) - the general information

Components of brake system with ABS


1 — Control lamp ABS 2 — the Control lamp of level of a brake liquid 3 — Hydraulic pump ABS 4 — the Hydraulic modulator 5 — the Gauge-switch of stoplights 6 — the Site of a diagnostic socket	7 — the Pulse disk (an alarm rotor) back wheel gauge 8 — the Gauge of frequency of rotation of a back wheel 9 — the Bolt 10 — the Pulse disk (an alarm rotor) forward wheel gauge 11 — the Gauge of frequency of rotation of a forward wheel

Function chart of brake system with ABS


Д — the Wheel gauge ТМ — the Brake mechanism 1 — the Electrohydraulic valve 2 — ГТЦ	3 — the Pump 4 — Valves of diagonal division of contours 5 — the Tank of a brake liquid 6 — ECU

Arrangement of the gauge of frequency of rotation of a forward wheel


1 — the Wheel gauge	2 — the Pulse disk (rotor)

Arrangement of the gauge of frequency of rotation of a back wheel


1 — the Brake board 2 — the Brake drum 3 — the Nave	4 — the Wheel gauge 5 — the Pulse disk (rotor)

Cars are completed ABS firm ITT Automotive Europe manufactures. Into the complete set enter: the amplifier 9 ", ГТЦ тандемного type (23.8 mm), the hydraulic modulator and connecting lines. A carving for connection of hydraulic lines of the right and left wheels on modulator assemblage various - М12х1 and М10х1 accordingly.

ABS enters into a standard complete set of some models, on the others can be established in addition. Into system structure enter the hydraulic modulator with the electronic block of management established on it (ECU) and four wheel gauges. The modulator is equipped by hydraulic electromagnetic valves (on two on each of brake mechanisms [one inlet and one final]) and электроприводной the pump. A system problem is prevention of premature blocking of wheels of the car at sharp braking. The given purpose is reached at the expense of instant modulations of pressure in hydraulic contours of brake mechanisms of wheels.

Operation of electromagnetic valves of the modulator operates ECU, continuously receiving the information on speed of rotation of each of wheels of the car from four wheel gauges. Analyzing arriving signals, ECU defines current speed of movement of the car and uses it as a reference point at definition of the moment of the beginning of blocking of each of wheels. In normal conditions the brake system functions as usual, not equipped ABS.

At the moment of the beginning of blocking of any of wheels ECU gives out a command on operation of the corresponding final electromagnetic valve (ов) the hydraulic modulator. As a result given brake mechanism () is isolated from ГТЦ and pressure in it ceases to raise.

If speed of rotation of the given wheel (wheels) continues to decrease, the management block gives out a command on opening inlet electromagnetic the valve (ов) and activates электроприводной the pump which pumps out a brake liquid back in ГТЦ, returning rotation freedom to the blocked wheel (ам). As soon as speed of rotation of a wheel (wheels) rises to comprehensible value, the pump is disconnected, and the electromagnetic valve () reestablishes communication of a hydraulic contour of the corresponding brake mechanism (ов) with ГТЦ. The cycle can repeat set of times in a second, allowing to keep the control over driving at sharp braking without dependence from a condition of a road covering.

Functioning of electromagnetic valves and the returnable pump causes pulsations in a hydraulic contour, therefore pushes of a pedal of a foot brake during functioning ABS are quite natural phenomenon and should not cause anxiety.

Functioning ABS completely is based on electric signals developed by wheel gauges. In order to avoid false operations of the modulator, ECU it is equipped by the special control contour tracing all signals arriving on the block. In case of receipt of a doubtful signal, or at revealing of signs of decrease in target pressure of the storage battery, on an instrument guard the corresponding control lamp informing the driver about refusal ABS lights up. The brake system thus continues to function in a usual mode, providing adequate braking of the car.

During car operation watch tightness of connections of a hydraulic path and an electroconducting condition. Components ABS do not require additional service.

In case of infringement of functioning ABS the car should be driven away on a company car repair shop where will be made full diagnostics of system with application of the special input reader and corresponding repair.