2004 DAEWOO LACETTI Rear switch

4F – 30IANTILOCK BRAKE SYSTEM
DAEWOO V–121 BL4
DTC C0045 – Left Rear Wheel Speed Sensor Circuit Malfunction
StepActionValue(s)YesNo
1Examine the wheel speed sensor.
Are there any signs of physical damage?–Go to Step 3Go to Step 2
21. Turn the ignition switch to LOCK.
2. Disconnect the left rear wheel speed sensor
connector.
3. Use a digital voltmeter (DVM) to measure the
resistance between the sensor terminals.
Is the resistance within the specified value at
approximately 25°C (77°F)?1280–1920 WGo to Step 4Go to Step 3
3Replace the wheel speed sensor.
Is the repair complete?–System OK–
41. Switch the DVM to the AC millivolt range.
2. Measure the voltage output of between the
wheel speed sensor terminals while rotating
the wheel about 1 revolution every 2 seconds.
Is the output within the specified value?
120 vGo to Step 6Go to Step 5
5Replace the speed sensor or the toothed wheel as
required.
Is the repair complete?–System OK–
61. Disconnect the harness from the EBCM.
2. Connect a DVM between ground and one ter-
minal of the wheel speed connector.
3. Turn the ignition to ON.
4. Repeat the above test for the other terminal of
the wheel speed connector.
Is the voltage for either of these terminals within the
specified value?> 1 vGo to Step 7Go to Step 8
7Repair the short to voltage in the affected circuit.
Is the repair complete?–System OK–
81. Turn the ignition switch to LOCK.
2. Measure the resistance to ground from termi-
nal 8 at the harness EBCM connector.
3. Measure the resistance to ground from termi-
nal 9 at the harness EBCM connector.
Is the resistance at either circuit less than the speci-
fied value?Go to Step 9Go to Step 10
9Repair the short to ground in the affected circuit.
Is the repair complete?–System OK–
101. Measure the resistance between terminal 8 at
the harness EBCM connector and the harness
wheel speed sensor connector terminal con-
nected to the RED wire.
2. Measure the resistance between terminal 9 at
the harness EBCM connector and the harness
wheel speed sensor connector terminal con-
nected to the BLK wire.
Is the resistance on either circuit within the specified
value?> 5 WGo to Step 11Go to Step 12

ANTILOCK BRAKE SYSTEM 4F – 33
DAEWOO V–121 BL4
DTC C0050 – Right Rear Wheel Speed Sensor Circuit Malfunction
StepActionValue(s)YesNo
1Examine the wheel speed sensor.
Are there any signs of physical damage?–Go to Step 3Go to Step 2
21. Turn the ignition switch to LOCK.
2. Disconnect the left rear wheel speed sensor
connector.
3. Use a digital voltmeter (DVM) to measure the
resistance between the sensor terminals.
Is the resistance within the specified value at
approximately 25°C (77°F)?1280–1920 WGo to Step 4Go to Step 3
3Replace the wheel speed sensor.
Is the repair complete?–System OK–
41. Switch the DVM to the AC millivolt range.
2. Measure the voltage output of between the
wheel speed sensor terminals while rotating
the wheel about 1 revolution every 2 seconds.
Is the output within the specified value?
120 vGo to Step 6Go to Step 5
5Replace the speed sensor or the toothed wheel as
required.
Is the repair complete?–System OK–
61. Disconnect the harness from the EBCM.
2. Connect a DVM between ground and one ter-
minal of the wheel speed connector.
3. Turn the ignition to ON.
4. Repeat the above test for the other terminal of
the wheel speed connector.
Is the voltage for either of these terminals within the
specified value?> 1 vGo to Step 7Go to Step 8
7Repair the short to voltage in the affected circuit.
Is the repair complete?–System OK–
81. Turn the ignition switch to LOCK.
2. Measure the resistance to ground from termi-
nal 1 at the harness EBCM connector.
3. Measure the resistance to ground from termi-
nal 2 at the harness EBCM connector.
Is the resistance at either circuit less than the speci-
fied value?Go to Step 9Go to Step 10
9Repair the short to ground in the affected circuit.
Is the repair complete?–System OK–
101. Measure the resistance between terminal 1 at
the harness EBCM connector and the harness
wheel speed sensor connector terminal con-
nected to the WHT wire.
2. Measure the resistance between terminal 2 at
the harness EBCM connector and the harness
wheel speed sensor connector terminal con-
nected to the GRY wire.
Is the resistance on either circuit within the specified
value?> 5 WGo to Step 11Go to Step 12

ANTILOCK BRAKE SYSTEM 4F – 39
DAEWOO V–121 BL4
J3B14F09
DLC
(Data Link
Connector)
EBCM
DK BLUDK BLU
BLK/WHTC202
C110
11 2
1912 19
G106
DIAGNOSTIC TROUBLE CODE (DTC) C0080/C0085
LEFT REAR INLET AND OUTLET VALVE SOLENOID
FAULT
Circuit Description
The solenoid valve coil circuits are supplied with power
from the battery when the valve relay is energized.
Switched ground is provided by the electronic brake con-
trol module (EBCM) to each coil.
Diagnosis
This procedure checks whether the left rear inlet and outlet
valves are functioning.
Cause(s)
S A valve has failed.S A solenoid coil is open or shorted.
Fail Action
ABS is disabled, and the ABS warning lamp is turned ON
for the remainder of the ignition cycle. EBD is disabled. If
the failure is intermittent, the EBCM will enable the system
at the next ignition cycle and set a history DTC.
Test Description
The number(s) below refer to step(s) on the diagnostic
table.
1. This begins the test of the inlet valve.
3. This tests the outlet valve.

4F – 40IANTILOCK BRAKE SYSTEM
DAEWOO V–121 BL4
DTC C0080/C0085 – Left Rear Inlet and Outlet Valve Solenoid Fault
StepActionValue(s)YesNo
11. Raise and suitably support the vehicle at the
corner being tested.
2. Turn the ignition switch to ON.
3. Install the scan tool to the Data Link Connector
(DLC) and select ”Wheel rear left” to begin the
solenoid tests at that wheel. This will test both
the inlet and the outlet valves.
4. When the scan tool indicates ”Pressure hold,”
depress and hold the brake pedal until the end
of the test.
5. Have an assistant attempt to rotate the wheel.
Can the wheel be rotated?–Go to Step 2Go to Step 6
21. Maintain pressure on the brake pedal.
2. When the scan tool indicates ”Pressure in-
crease,” have an assistant attempt to rotate the
wheel again.
Can the wheel be rotated now?–Go to Step 6Go to Step 3
31. Maintain pressure on the brake pedal.
2. When the scan tool indicates ”Pressure release
on,” have an assistant attempt to rotate the
wheel again.
Can the wheel be rotated?–Go to Step 4Go to Step 6
41. Release brake pedal pressure when the scan
tool indicates ”Pressure release off.”
2. Clear all DTCs.
3. Road test the vehicle.
Does the DTC set again?–Go to Step 6Go to Step 5
51. Check the wiring harness and connector termi-
nals for an intermittent problem.
2. Repair any problem found.
Is the repair complete?–System OK–
6Replace the ABS unit.
Is the repair complete?–System OK–

ANTILOCK BRAKE SYSTEM 4F – 41
DAEWOO V–121 BL4
J3B14F09
DLC
(Data Link
Connector)
EBCM
DK BLUDK BLU
BLK/WHTC202
C110
11 2
1912 19
G106
DIAGNOSTIC TROUBLE CODE (DTC) C0090/C0095
RIGHT REAR INLET AND OUTLET VALVE SOLENOID
FAULT
Circuit Description
The solenoid valve coil circuits are supplied with power
from the battery when the valve relay is energized.
Switched ground is provided by the electronic brake con-
trol module (EBCM) to each coil.
Diagnosis
This procedure checks whether the right rear inlet and out-
let valves are functioning.
Cause(s)
S A valve has failed.S A solenoid coil is open or shorted.
Fail Action
ABS is disabled, and the ABS warning lamp is turned ON
for the remainder of the ignition cycle. EBD is disabled. If
the failure is intermittent, the EBCM will enable the system
at the next ignition cycle and set a history DTC.
Test Description
The number(s) below refer to step(s) on the diagnostic
table.
1. This begins the test of the inlet valve.
3. This tests the outlet valve.

4F – 42IANTILOCK BRAKE SYSTEM
DAEWOO V–121 BL4
DTC C0090/C0095 – Right Rear Inlet and Outlet Valve Solenoid
Fault
StepActionValue(s)YesNo
11. Raise and suitably support the vehicle at the
corner being tested.
2. Turn the ignition switch to ON.
3. Install the scan tool to the Data Link Connector
(DLC) and select ”Wheel rear right” to begin
the solenoid tests at that wheel. This will test
both the inlet and the outlet valves.
4. When the scan tool indicates ”Pressure hold,”
depress and hold the brake pedal until the end
of the test.
5. Have an assistant attempt to rotate the wheel.
Can the wheel be rotated?–Go to Step 2Go to Step 6
21. Maintain pressure on the brake pedal.
2. When the scan tool indicates ”Pressure in-
crease,” have an assistant attempt to rotate the
wheel again.
Can the wheel be rotated now?–Go to Step 6Go to Step 3
31. Maintain pressure on the brake pedal.
2. When the scan tool indicates ”Pressure release
on,” have an assistant attempt to rotate the
wheel again.
Can the wheel be rotated?–Go to Step 4Go to Step 6
41. Release brake pedal pressure when the scan
tool indicates ”Pressure release off.”
2. Clear all DTCs.
3. Road test the vehicle.
Does the DTC set again?–Go to Step 6Go to Step 5
51. Check the wiring harness and connector termi-
nals for an intermittent problem.
2. Repair any problem found.
Is the repair complete?–System OK–
6Replace the ABS unit.
Is the repair complete?–System OK–

ANTILOCK BRAKE SYSTEM 4F – 69
DAEWOO V–121 BL4
EBD (ELECTRONIC BRAKE FORCE
DISTRIBUTION) SYSTEM
As an add–on logic to the ABS base algorithm, EBD works
in a range in which the intervention thresholds for ABS
control are not reached yet.
EBD ensures that the rear wheels are sensitively moni-
tored for slip with respect to the front axle. If slip is de-
tected, the inlet valves for the rear wheels are switched to
pressure hold to prevent a further increase in pressure at
the rear–wheel breaks, thus electronically reproducing a
pressure–reduction function at the rear–wheel brakes.
THE BENEFITS OF EBD
S Elimination of conventional proportioning valve.
S EBD utilizes the existing rear axle wheel speed
sensor to monitor rear wheel slip.
S Based on many variables in algorithm a pressure
hold, increase and/or decrease pulsetrain may be
triggered at the rear wheels insuring vehicle stabil-
ity.
S Vehicle approaches the ideal brake force distribu-
tion. (front to rear)
S Constant brake force distribution during vehicle life-
time.
S EBD function is monitored via ABS safety logic.
(conventional proportioning valves are not monitor-
able)
S ”Keep alive” function.

ANTILOCK BRAKE SYSTEM 4F – 71
DAEWOO V–121 BL4
TIRES AND ABS/EBD
Replacement Tires
Tire size is important for proper performance of the ABS
system. Replacement tires should be the same size, load
range, and construction as the original tires. Replace tires
in axle sets and only with tires of the same tire perfor-
mance criteria (TPC) specification number. Use of any
other size or type may seriously affect the ABS operation.
TIRES AND ABS/EBD
Notice : There is no serviceable or removable EEPROM.
The EBCM must be replaced as an assembly.
The EBCM is attached to the hydraulic unit in the engine
compartment. The controlling element of ABS 5.3 is a mi-
croprocessor–based EBCM. Inputs to the system include
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 K of Data Link Connector (DLC) for service diagnostic
tools and assembly plant 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 sole-
noids to reduce brake pressure to the wheel approaching
lockup. Once the wheel regains traction, brake pressure
is increased until the wheel again begins to approach lock-
up. This 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 (except
the serial data link), and each output for proper operation.
If it detects any system malfunction, the EBCM will store
a DTC in nonvolatile memory (EEPROM) (DTCs will not
disappear if the battery is disconnected). Refer to ”Self
Diagnostics” in this section for more detailed information.
FRONT WHEEL SPEED SENSOR
The front wheel speed sensors are of a variable reluctance
type. Each sensor is attached to the steering knuckle,
close to a toothed ring. The result, as teeth pass by the
sensor, is an AC voltage with a frequency proportional to
the speed of the wheel. The magnitude of the voltage and
frequency increase with increasing speed. The sensor is
not repairable, nor is the air gap adjustable.
FRONT WHEEL SPEED SENSOR
RINGS
The toothed ring mentioned above is pressed onto the
wheel–side (outer) constant velocity joint. Each ring con-
tains 47 equally spaced teeth. Exercise care during ser-
vice procedures to avoid prying or contacting this ring. Ex-cessive contact may cause damage to one or more teeth.
If the ring is damaged, the wheel–side constant velocity
joint must be replaced.
REAR WHEEL SPEED SENSOR AND
RINGS
The rear wheel speed sensors operate in the same man-
ner as the front wheel speed sensors. They incorporate a
length of flexible harness with the connector attached to
the end of the harness. The rear wheel speed rings are in-
corporated into the hub assemblies and cannot be re-
placed separately, but require replacement of the rear
hub/bearing assembly.
VALUE RELAY AND PUMP MOTOR
RELAY
The valve relay and the motor pump relay are located in-
side the electronic brake control module (EBCM) and are
not replaceable. If one should fail, replace the EBCM.
WIRING HARNESS
The wiring harness is the mechanism by which the elec-
tronic brake control module (EBCM) is electrically con-
nected to power and to ground, to the wheel speed sen-
sors, the fuses, the switches, the indicators, and the serial
communications port. The components, considered part
of the wiring harness, are the wires that provide electrical
interconnection, and connectors (terminals, pins, con-
tacts, or lugs) that provide an electrical/mechanical inter-
face from the wire to a system component.
INDICATORS
The electronic brake control module (EBCM) continuously
monitors itself and the other ABS components. If the
EBCM detects a problem with the system, the amber ABS
indicator will light continuously to alert the driver to the
problem. An illuminated ABS indicator indicates that the
ABS system has detected a problem that affects the op-
eration of ABS. No antilock braking will be available. Nor-
mal, non–antilock brake performance will remain. In order
to regain ABS braking ability, the ABS must be serviced.
The red BRAKE indicator will be illuminated when the sys-
tem detects a low brake fluid level in the master cylinder
or when the parking brake switch is closed (the parking
brake is engaged) or EBD system is diabled.
WARNING : EBD INDICATOR LAMP WIRING IS CON-
NECTED TO THE PARKING BRAKE LAMP. IF THE
PARKING BRAKE LAMP IS TURNED ON WHEN YOU
DRIVING, CHECKING ON WHETHER THE PARKING
BRAKE LEVER IS ENAGED OR THE BRAKE FLUID
LEVEL IS LOW. IF THE SYSTEM HAS NO PROBLEM,
THE EBD SYSTEM IS WORKING IMPROPERLY. THE
EBD SYSTEM MUST BE SERVICED.