2003 DAEWOO MATIZ brake

4F–4 ANTILOCK BRAKE SYSTEM
DAEWOO M-150 BL2
feed back to the master cylinder and brake pedal.
D107E005
Return Pump Motor
The motor drives two pump elements through the ec-
centric wheel on its shaft.
Return Pump
Description: Each pump element consists of a fixed
displacement piston driven by an eccentric on the end of
the eccentric motor. It has two check valves (inlet and
outlet) and is fed with fluid by the low pressure accumu-
lator.
Operation:
Compression stroke: the pump is filled via the inlet ball
seat, then the motor eccentric rotates moving the piston
to displace the fluid. After the pressure build-up closes
the inlet valve the piston displacement increases the
pressure until the outlet ball opens. The outlet pressure
will continue to increase for the rest of the piston stroke.
Return Stroke: The piston retracts, forced by its spring,
as the motor eccentric returns to its low end position.
The pressure at the inlet side of the outlet ball then de-
creases due to the displaced volume and the pressure
difference across this ball holds it closed.
The pressure at the outlet side of the inlet ball seat,
which is set to open at a certain pressure level also de-
creases until this valve opens. With the outlet ball
closed, the pump is filled with additional fluid from the
low pressure accumulator.
The pressure will continue until a stall point is reached
and compression of the piston cannot generate enough
differential pressure anymore to open the outlet ball
seat.
D17E006A
Return Pump
Return Pump
Motor(0.12~0.16 in.)
EBCM (ELECTRONIC BRAKE
CONTROL MODULE)
Notice: There is no serviceable. The EBCM must be re-
placed as an assembly.
The EBCM is attached to the hydraulic unit in the engine
compartment. The controlling element of ABS is a mi-
croprocessor-based EBCM. Inputs to the system in-
clude the four wheel speed sensors, the stoplamp
switch, the ignition switch, and the unswitched battery
voltage. There is an output to a bi-directional serial data
link, located in pin M of the assembly line diagnostic link
(ALDL), for service diagnostic tools and assembly plat
testing.
The EBCM monitors the speed of each wheel. If any
wheel begins to approach lockup and the brake switch is
closed (brake pedal depressed), the EBCM controls the
dump valve to reduce brake pressure to the wheel ap-
proaching lockup. Once the wheel regains traction,
brake pressure is increased until the wheel again begins
to approach lockup. The cycle repeats until either the
vehicle comes to a stop, the brake pedal is released or
no wheels approach lockup.
Additionally, the EBCM monitors itself, each input (ex-
cept the serial data link), and each output for proper op-
eration. If it detects any system malfunction, the EBCM
will store a DTC in nonvolatile memory (DTCs will not
disappear if the battery is disconnected).

ANTILOCK BRAKE SYSTEM 4F–5
DAEWOO M-150 BL2
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
DAEWOO M-150 BL2
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
DAEWOO M-150 BL2
HYDRAULIC FLUID FLOW DIAGRAMS
Master Cylinder
High Pressure Attenuator
High Pressure Attenuator
Return Pump Motor
Return Pump Return Pump
RR
Isolation Valve
Low
Pressure
AccumulatorFL
Isolation Valve
RR Dump ValveFL
Dump
ValveFR
Isolation Valve
Low Pressure
Accumulator
FR Dump ValveRL
Dump
ValveRL
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
DAEWOO M-150 BL2
Master Cylinder
High Pressure Attenuator
High Pressure Attenuator
Return Pump Motor
Return Pump Return Pump
Low
Pressure
Accumulator
Low Pressure
Accumulator
RRFL FR
RL
D17E206A
RR
Isolation ValveFL
Isolation Valve
RR Dump ValveFL
Dump
ValveFR
Isolation Valve
FR Dump ValveRL
Dump
ValveRL
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.

ANTILOCK BRAKE SYSTEM 4F–9
DAEWOO M-150 BL2
Master Cylinder
High Pressure Attenuator
High Pressure Attenuator
Return Pump Motor
Return Pump Return Pump
Low
Pressure
Accumulator
Low Pressure
Accumulator
RRFL FR
RL
D17E207A
RR
Isolation ValveFL
Isolation Valve
RR Dump ValveFL
Dump
ValveFR
Isolation Valve
FR Dump ValveRL
Dump
ValveRL
Isolation
Valve
DUMP MODE (PRESSURE DECREASE)
Once the pressure is isolated, it must be reduced to get the wheels rolling once again. This is accomplished by dump-
ing a portion of the brake fluid pressure into a low pressure accumulator (LPA).
The EBCM energizes the dump cartage coil(s) to open the dump cartridge, allowing fluid from the wheels to be
dumped into the LPA. This done with very short activation pulses opening and closing the dump cartridge passageway.
Brake pressure is lowered at the wheel and allows the wheel to begin spinning again.
The fluid taken from the wheels forces the spring back and is stored in the LPA. A portion of the fluid also primes the
pump. The dump cartridges are operated independently to control the deceleration of the wheel.

4F–10 ANTILOCK BRAKE SYSTEM
DAEWOO M-150 BL2
Master Cylinder
High Pressure Attenuator
Return Pump Motor
Return Pump Return Pump
Low Pressure
Accumulator
RRFL FR
RL
D17E208A
RR
Isolation Valve
Low
Pressure
AccumulatorFL
Isolation Valve
RR Dump ValveFL
Dump
ValveFR
Isolation Valve
FR Dump ValveRL
Dump
ValveRL
Isolation
Valve High Pressure Attenuator
REAPPLY MODE (PRESSURE INCREASE)
This reapply sequence is initiated to obtain optimum braking. The isolation valve is momentarily pumped open to allow
master cylinder and pump pressure to reach the brakes. This controlled pressure rise continues unitl the wheel is at
optimum brake output or until the brake pressure is brough up to the master cylinder output pressure.
If more pressure is required, more fluid is drawn from the master cylinder and applied to the brakes. The driver may
feel slight pedal pulsations, or pedal drop, this is normal and expected.
As fluid is reapplied to the wheel, they begin to slow down. If they approach imminent lockup again, the EBCM will
isolate, dump and reapply again. The control cycle (isolation, dump, reapply) occurs in milli-second intervals, allowing
seveal cycles to occur each second.
It is a much faster and more controlled way of “pumping the pedal”.

ANTILOCK BRAKE SYSTEM 4F–11
DAEWOO M-150 BL2
Master Cylinder
High Pressure Attenuator
High Pressure Attenuator
Return Pump Motor
Return Pump Return Pump
Low Pressure
Accumulator
RRFL FR
RL
D17E209A
RR
Isolation Valve
Low
Pressure
AccumulatorFL
Isolation Valve
RR Dump ValveFL
Dump
ValveFR
Isolation Valve
FR Dump ValveRL
Dump
ValveRL
Isolation
Valve
PROPORTIONING FUNCTION
If the rear wheels lock formerly during braking, the vehicle may lose the stability. Therefore to prevent this, the ECM
processes the speed sensor signal and brake signal to determine when the rear wheels are tending to lock up. The
EBCM then actuates the rear wheel isolation valves to reduce the rear brake pressure and keep the wheels rolling.