Opel Frontera UE. Manual - part 1376

 

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Opel Frontera UE. Manual - part 1376

 

 

BRAKE CONTROL SYSTEM

5A–3

General Description

The Anti-lock Brake System (ABS) works on all four 
wheels. A combination of wheel speed  sensor and 
Electronic Hydraulic Control Unit (EHCU) can determine 
when a wheel is about to stop turning and adjust  brake 
pressure to maintain best braking.

This system helps the driver maintain greater control of 
the  vehicle under heavy braking conditions.

NOTE:  The Electronic Hydraulic Control Unit (EHCU) 
comprises the Hydraulic Unit (H/U) and the coil 
Integrated Module.

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(1) Electronic
(2) Hydraulic
(3) Hydraulic Unit (H/U)
(4) Coil Integrated Module

(5) Front Wheel Speed Sensor
(6) Rear Wheel Speed Sensor
(7) Proportioning and Bypass (P&B) Valve

SECTION

5A–4

BRAKE CONTROL SYSTEM

Functional Description

Hydraulic Unit (H/U)

Solenoid Valve

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(1) Isolation Valve

(2) Dump valve

SECTION

BRAKE CONTROL SYSTEM

5A–5

Normal Braking

During normal (non anti-lock) braking, the solenoid 
valves are without current and closed due to spring 
force.

Brake fluid travels through the centre of the normally 
open isolation valve around the normally closed dump 
valve and on to the brake pistons.

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(1) Brake

(2) Master Cylinder

SECTION

5A–6

BRAKE CONTROL SYSTEM

Pressure Isolation (Pressure Maintain)

The electro-hydraulic control unit is activated when the 
brakes are applied which sends a signal to the coil 
integrated module to prepare for a possible anti-lock 
stop.
If the information from the wheel speed sensors 
indicates excessive wheel deceleration (imminent 
lockup), the first step in the anti-lock sequence is to 
isolate the brake pressure being applied by the brake 

pedal.
The microprocessor in the coil integrated module sends 
a voltage to the coil to energize and close the isolation 
valve. This prevents any additional fluid pressure 
applied by the brake pedal from reaching the wheel. 
With the isolation valves closed, further unnecessary 
increase in the brake pressure is therefore prevented.

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(1) Brake

(2) Master Cylinder

SECTION

 

 

 

 

 

 

 

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