Mitsubishi Eclipse. Technical Information Manual (1994) - part 63

 

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ABS HYDRAULIC PRESSURE FUNCTION DIAGRAM

The ABS for FWD operates independently on the

right and left front wheels and controls each solenoid

hydraulic pressure is simultaneously reduced in both

valve by sensing each wheel speed sensor. It 

rear wheels through the use of a plunger valve.

trols the solenoid valve for the rear wheels by using

Select-low: this is a method of providing the same

the rear wheel speed sensor select-low for the right

hydraulic control to both wheels when either wheel

and left rear wheels. In other words, when either

is about to lock, matching it to the side about to

the right or left rear wheel is about to lock, the

lock, or a method to control by matching pressure
to the low side.

solenoid valve for the rear wheels is activated and

Solenoid

valve
control

Wheel speed sensor

Left front 

wheel

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 Master cylinder

valve
control

Hydraulic unit

- - - - _

Wheel speed sensor 

 

Right

 whee

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left front

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Solenoid
valve
control

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  F

   

 Wheel speed sensor

Proportioning valve

.

Left rear wheel

Right rear wheel

 

 

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WHEEL SPEED SENSOR
The wheel speed sensor is a type of pulse generator

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For a rear wheel, the rotor (43 teeth) is mounted

consisting of a rotor rotating at the same 

on the rear hub, and the speed sensor mounted

as the wheel and a speed sensor secured to the

on the knuckle.

knuckle.

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For both front and rear wheels, the spacing

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For a front wheel, the rotor (43 teeth) is mounted

between the sensor and rotor is adjustment-free.

on the front drive shaft and the speed sensor

mounted on the knuckle.

FRONT

REAR

Knuckle ,

, ,

Drive shaft

Stop light switch

To stop light

sensor

Knuckle

Rear hub

sensor

STOP LIGHT SWITCH
The signal from the stop light switch is input to the ABS-ECU
as a brake pedal movement signal.
When the brake pedal is depressed, the stop light switch circuit

contact closes (ON), and when the brake pedal is released,

it opens (OFF). When the contact is closed, the output voltage
is at the battery voltage level (HIGH), and when it is opened,

the output voltage is at about   V (LOW).

 

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HYDRAULIC UNIT (HU)

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The HU, elastically supported by the shield plate

at the front left of the engine room, consists
of a motor pump, plunger valve, reservoir and

three solenoid valves.

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The HU, positioned between the brake master
cylinder and each wheel cylinder, is a hydraulic
circuit split into two systems associated with
the normal X pipings when the ABS is inactive.

Solenoid

Wheel

When the ABS is active, the motor is operated

by a signal from the ABS-ECU to let the pump
generate a hydraulic pressure required to return

fluid against master cylinder pressure. At the
same time, three solenoid valves are operated
to control the hydraulic pressure that acts on
the wheel cylinder.

Solenoid valve and plunger valve

Refer to 1991 3000GT Technical Information Manual (Pub. No. PXSE9001).

Hydraulic unit

Master cylinder

 

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Pump motor relay

3 0

 

warning

Relay Box

The motor relay and valve relay are mounted on the hydraulic

unit.

MOTOR RELAY

This relay turns the pump motor in the HU ON and OFF.

NOTE
Refer to the section on ECU control for ON/OFF control.

VALVE RELAY
This relay turns current to the solenoid valve in the HU ON
and OFF.

NOTE
Refer to the section on ECU control for ON/OFF control.

ABS WARNING LIGHT
This light lights up in case if there is a breakdown in the ABS.

Furthermore, it checks whether the bulb is burnt out when

the engine is started.

NOTE
Refer to the section on ECU Control for warning light control.