Page 567 of 1184

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.
Page 570 of 1184
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.
Page 572 of 1184
ANTILOCK BRAKE SYSTEM 4F–13
DAEWOO M-150 BL2
COMPONENT LOCATOR
ABS
D17E401A
1. Hydraulic Modulator Unit
2. Electronic Brake Control Module (EBCM)
3. Bolt
4. Upper Mounting Bracket
5. Grommet6. Lower Mounting Bracket
7. Bracket Grommet
8. Rear Wheel Speed Sensor
9. Front Wheel Speed Sensor
Page 575 of 1184

4F–16 ANTILOCK BRAKE SYSTEM
DAEWOO M-150 BL2
DIAGNOSTIC INFORMATION AND PROCEDURES
D17E301A
DIAGNOSTIC TROUBLE CODE (DTC) 0354
LEFT FRONT WHEEL SPEED SENSOR CIRCUIT OPEN OR SHORTED
Circuit Description
As a toothed ring passes by the wheel speed sensor,
changes in the electromagnetic field cause the wheel
speed sensor to produce a sinusoidal (AC) voltage sig-
nal whose frequency is proportional to the wheel speed.
The magnitude of this signal is directly related to wheel
speed and the proximity of the wheel speed sensor to
the toothed ring often referred to as the air gap.
Diagnosis
This test detects a short to battery, ground, or open in
the left front wheel speed sensor circuit.
Cause(s)
The wheel speed circuit is open or shorted to the bat-
tery or ground.
There is a loose connection in the wheel speed cir-
cuit.
The wheel speed sensor resistance is very high.
The EBCM is malfunctioning.Fail Action
This is a critical operational fault. The ABS is disabled
and the ABS warning lamp is turned on. The proportion-
ing is operation.
Diagnostic Aids
An ‘‘intermittent’’ malfunction may be caused by a poor
connection, rubbed through wire insulation, or a wire
that is broken inside the insulation.
Thoroughly check any circuitry suspected of causing the
intermittent complaint. Look for backed out terminals,
improper mating, broken locks, improperly formed or
damaged terminals, poor terminal to wiring connections,
or physical damage to the wiring harness.
Wheel speed sensor resistance will increase as the sen-
sor temperature increases.
When replacing a wheel speed sensor, inspect the sen-
sor terminals and harness connector for corrosion and/
or water intrusion. If evidence of corrosion or water
Page 576 of 1184

ANTILOCK BRAKE SYSTEM 4F–17
DAEWOO M-150 BL2
intrusion exists, replace the wheel speed sensor har-
ness. If replacing a wheel speed sensor harness, in-
spect the sensor terminals. If you find evidence of
corrosion or water intrusion, replace the wheel speed
sensor. Refer to “Front Wheel Speed Sensor” in this
section.Important: Wheel speed sensor intermittent malfunc-
tions may be difficult to locate. Take care not to disturb
any electrical connections before performing an indi-
cated step of this table. That will ensure that an intermit-
tent connection will not be corrected before the source
of the malfunction is found.
DTC 0354 – Left Front Wheel Speed Sensor Circuit Open or Shorted
Step Action Value(s) Yes No
1
1. Turn the ignition switch to OFF.
2. Disconnect the EBCM harness connector from
the EBCM.
3. Use a digital voltmeter (DVM) to measure the
resistance between terminals 14 and 25 of
connector on the EBCM harness.
Is the resistance within the specified value?
1.0 k to
1.5 k
Go to Step 4
Go to Step 2
2
1. Disconnect the harness from the left front wheel
speed sensor.
2. Use a DVM to measure the resistance between
terminals 1 and 2 of the left front wheel speed
sensor connector.
Is the resistance within the specified value?
1.0 k to
1.5 k
Go to Step 4
Go to Step 3
3
Replace the wheel speed sensor.
Is the repair complete?
–
System OK
–
4
Use a DVM to measure the resistance between ter-
minal 14 of the EBCM harness connector, and termi-
nal 1 of the left front wheel speed sensor harness
connector.
Is the resistance within the specified value?
less than 1
Go to Step 6
Go to Step 5
5
1. Repair the high resistance in circuit DK BLU.
2. If the wheel speed sensor harness is damaged,
replace it.
Is the repair complete?
–
System OK
–
6
Use a DVM to measure the resistance between ter-
minal 25 of the EBCM harness connector, and termi-
nal 2 of the left front wheel speed sensor harness
connector.
Is the resistance within the specified value?
less than 1
Go to Step 8
Go to Step 7
7
1. Repair the high resistance in circuit YEL.
2. If the wheel speed sensor harness is damaged,
replace it.
Is the repair complete?
–
System OK
–
8
Use a DVM to measure the resistance between
ground and terminal 14 of the EBCM connector.
Does the DVM show the specified value?
Go to Step 10
Go to Step 9
9
Repair the short to ground in circuit DK BLU.
Is the repair complete?
–
System OK
–
Page 577 of 1184

4F–18 ANTILOCK BRAKE SYSTEM
DAEWOO M-150 BL2
DTC 0354 – Left Front Wheel Speed Sensor Circuit Open or Shorted (Cont’d)
Step Action Value(s) Yes No
10
Use a DVM to measure the resistance between
ground and terminal 25 of the EBCM connector.
Does the DVM show the specified value?
Go to Step 12
Go to Step 11
11
Repair the short to ground in circuit YEL.
Is the repair complete?
–
System OK
–
12
1. Reconnect all of the connectors.
2. Turn the ignition to ON.
3. Use a DVM to measure the voltage between
ground and terminal 14 of EBCM connector.
Is the voltage within the specified value?
0 v
Go to Step 14
Go to Step 13
13
Repair the short to voltage in circuit DK BLU.
Is the repair complete?
–
System OK
–
14
Use a DVM to measure the voltage between ground
and terminal 25 of EBCM connector.
Is the voltage within the specified value?
0 v
Go to Step 16
Go to Step 15
15
Repair the short to voltage in circuit YEL.
Is the repair complete?
–
System OK
–
16
Replace the EBCM.
Is the repair complete?
–
System OK
–
Page 579 of 1184

4F–20 ANTILOCK BRAKE SYSTEM
DAEWOO M-150 BL2
D17E301A
DIAGNOSTIC TROUBLE CODE (DTC) 0355
LEFT FRONT WHEEL SPEED SENSOR POOR
AIR GAP OR MISSING TOOTH RING
Circuit Description
As a toothed ring passes by the wheel speed sensor,
changes in the electromagnetic field cause the wheel
speed sensor to produce a sinusoidal (AC) voltage sig-
nal whose frequency is proportional to the wheel speed.
The magnitude of this signal is directly related to wheel
speed and the proximity of the wheel speed sensor to
the toothed ring often referred to as the air gap.
Diagnosis
This test checks for the left front wheel speed equal to 0
km/h (0 mph) for greater than 6 km/h (3.8 mph).
Cause(s)
The tooth ring is missing.
The air gap exceeds the required specifications.
Fail Action
This is a critical operational fault. The ABS is disabled
and the ABS warning lamp is turned on. The proportion-
ing is operation.Diagnostic Aids
An ‘‘intermittent’’ malfunction may be caused by a poor
connection, rubbed through wire insulation, or a wire
that is broken inside the insulation.
Thoroughly check any circuitry suspected of causing the
intermittent complaint. Look for backed out terminals,
improper mating, broken locks, improperly formed or
damaged terminals, poor terminal to wiring connections,
or physical damage to the wiring harness.
Wheel speed sensor resistance will increase as the sen-
sor temperature increases.
When replacing a wheel speed sensor, inspect the sen-
sor terminals and harness connector for corrosion and/
or water intrusion. If evidence of corrosion or water
intrusion exists, replace the wheel speed sensor har-
ness. If replacing a wheel speed sensor harness, in-
spect the sensor terminals. If you find evidence of
corrosion or water intrusion, replace the wheel speed
Page 580 of 1184
ANTILOCK BRAKE SYSTEM 4F–21
DAEWOO M-150 BL2
sensor. Refer to “Front Wheel Speed Sensor” in this
section.
Important: Wheel speed sensor intermittent malfunc-
tions may be difficult to locate. Take care not to disturbany electrical connections before performing an indi-
cated step of this table. That will ensure that an intermit-
tent connection will not be corrected before the source
of the malfunction is found.
DTC 0355 – Left Front Wheel Speed Sensor poor air Gap or Missing Tooth Ring
Step Action Value(s) Yes No
1
1. Turn the ignition switch to OFF.
2. Physically inspect the following components for
damage.
Wheel speed sensor is loose.
The air gap exceeds the required specifica-
tions.
The speed ring is missing or damaged.
3. Repair or replace the damaged.
Is the repair complete?
–
System OK
Go to Step 2
2
Replace the EBCM.
Is the repair complete?
–
System OK
–