Daewoo Matiz (2003 year). Manual - part 139

ANTILOCK BRAKE SYSTEM  4F – 5

D107E001

WHEEL SPEED SENSORS AND
RINGS

Front wheel speed sensors are installed to the front
knuckle and rear wheel speed sensors are installed to
the backing plate.
Wheel speed sensors are no serviceable. And the air
cap is not adjusted. Front wheel speed sensor ring is
pressed onto the drive axle shaft. Each ring contains 40
equally spaced teeth. Exercise care during service pro-
cedures to avoid prying or contacting this ring. Exces-
sive contact may cause damage to one or more teeth.
Rear wheel speed sensor rings are incorporated into the
hub drum.

D107E007

D107E008

ELECTRONIC BRAKE DISTRIBUTION

ABS features an enhanced algorithm which includes
control of the brake force distribution between the front
and rear axles. This is called Electronic Brake Distribu-
tion or Dynamic Rear Proportioning valve. In an unladen
car condition the brake efficiency is comparable to the
conventional system but for a fully loaden vehicle the ef-
ficiency of the Dynamic Rear Proportioning System is
higher due to the better use of rear axle braking capabili-
ty.

No indication is given to the driver when Dynamic Rear
Proportioning is activated. Also, DRP remains active
even in such cases where the anti-lock function of the
ABS is disabled.

D17E009A

Critical Brake Points

Ideal Distribution 
Fully Laden Vehicle

Ideal Distribution 
Lightly Loaded
Vehicle

Advanced Distribution with ABS

Regular Distribution without Dynamic
Rear Proportioning

Relative Front Brake Force

INDICATOR

It illuminates for four seconds immediately after the igni-
tion has been turned on to show that the anti-lock sys-
tem self-test is being carried out. If the light does not go
off after this time it means that there may be a problem
and ABS operation is not available.

If any malfunction or error, including an unplugged
EBCM connector, is detected during vehicle operation,
the light will come on, warning the driver that the ABS is
not operative and brake operation is in conventional,
non-ABS mode.

D17E010A

4F – 6  ANTILOCK BRAKE SYSTEM

EBCM CONNECTOR

A Connector has 31 pins which are shown below figure.
And a connector includes a warning switch which
grounds and lights the ABS warning lamp if there is No
EBCM unit plugged in, so that an indication is given that
ABS is not available.

D17E011A

Mechanical Switch

ANTILOCK BRAKE SYSTEM  4F – 7

HYDRAULIC FLUID FLOW DIAGRAMS

Master Cylinder

High Pressure Attenuator

High Pressure Attenuator

Return Pump Motor

Return Pump

Return Pump

RR
Isolation Valve

Low
Pressure
Accumulator

FL
Isolation Valve

RR Dump Valve

FL
Dump
Valve

FR
Isolation Valve

Low Pressure
Accumulator

FR Dump Valve

RL
Dump
Valve

RL
Isolation
Valve

RR

FL

FR

RL

D17E205A

NORMAL BRAKE MODE

During non-antilock braking, pressure is applied through the brake pedal and fluid comes from the master cylinder into
the hydraulic unit. The normally open isolation cartridge and normally closed dump cartridge would remain in these
positions to allow fluid pressure to the calipers and the wheel cylinders. And each wheel begins locking.

4F – 8  ANTILOCK BRAKE SYSTEM

Master Cylinder

High Pressure Attenuator

High Pressure Attenuator

Return Pump Motor

Return Pump

Return Pump

Low
Pressure
Accumulator

Low Pressure
Accumulator

RR

FL

FR

RL

D17E206A

RR
Isolation Valve

FL
Isolation Valve

RR Dump Valve

FL
Dump
Valve

FR
Isolation Valve

FR Dump Valve

RL
Dump
Valve

RL
Isolation
Valve

ISOLATION MODE (PRESSURE MAINTAIN)

If the information from the wheel speed sensors indicate excessive wheel deceleration (imminent lockup), the first step
in the antilock sequence is to isolate the brake pressure being applied by the driver. The EBCM sends a voltage to the
coil to energize and close the isolation valves by pulling down on the armature. This prevents any additional fluid pres-
sure applied by the driver from reaching the wheel. Though each channel of the 4-channel system can operate inde-
pendently, once any front channel (brake) sees excessive deceleration, both front isolation valves are energized and
close thus, with the isolation valves closed, further unnecessary increases in the brake pressure will be prohibited.