DAEWOO LACETTI 2004 Service Repair Manual

4F – 20IANTILOCK BRAKE SYSTEM
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
13Repair the contact at the I/P cluster connector termi-
nal A1.
Is the repair complete?–System OK–
14Check the wiring harnesses and connectors in cir-
cuit PPL/WHT from the I/P cluster terminal A1 to ter-
minal 21 of the EBCM connector.
Does the ohmmeter show the specified value?Go to Step 15Go to Step 16
15Repair the open or high resistance found.
Is the repair complete?–System OK–
16Check for continuity between terminal 19 of the ABS
connector and ground G106.
Does the ground connection match the specified val-
ue?0 WGo to Step 17Go to Step 18
17Replace the ABS unit.
Is the repair complete?–System OK–
18Repair the continuity problem between terminal 19
of the EBCM connector and ground G106.
Is the repair complete?–System OK–
191. Turn the ignition switch to LOCK.
2. Check fuse F4 in the I/P fuse block.
Is this fuse blown?–Go to Step 20Go to Step 21
20Replace fuse F4.
Is the repair complete?–System OK–
21Check fuse EF5 in the engine fuse block.
Is this fuse blown?–Go to Step 22Go to Step 23
22Replace fuse EF5.
Is the repair complete?–System OK–
23Measure the voltage at terminal 2 of the ignition
switch connector by backprobing.
Is the voltage within the specified value?11–14 vGo to Step 25Go to Step 24
241. Check circuit RED between terminal 4 of C105
at the engine fuse block and terminal 2 of the
ignition switch for continuity.
2. Repair any open or high resistance found.
Is the repair complete?–System OK–
251. Turn the ignition switch to ON.
2. Backprobe terminal 4 (PNK) of the ignition
switch connector.
Is the voltage within the specified value?11–14 vGo to Step 27Go to Step 26
26Replace the ignition switch.
Is the repair complete?–System OK–
271. Turn the ignition switch to LOCK.
2. Check circuit PNK from terminal 4 of the igni-
tion switch to fuse F4 in the I/P fuse block.
Does the ohmmeter show the specified value?Go to Step 28Go to Step 29

ANTILOCK BRAKE SYSTEM 4F – 21
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
28Repair the open or the high resistance.
Is the repair complete?–System OK–
291. Remove the instrument cluster.
2. Check circuit PNK from fuse F4 to terminal
B15 or A19 of the I/P cluster connector A.
3. Repair any open or high resistance found in a
wiring harness, splice pack, or connector.
Is the repair complete?–System OK–

4F – 22IANTILOCK BRAKE SYSTEM
DAEWOO V–121 BL4
SELF–DIAGNOSTICS
Important : The electronic brake control module (EBCM)
turns the valve relay off when a diagnostic trouble code
(DTC) is set. The scan tool will indicate that the valve relay
is off when it is used to monitor the data list. This is normal
and should not be considered a malfunction.
Important : For safety reasons it is recommended that the
vehicle not be driven with test equipment connected. Ex-
ception : for testing of wheel speeds provided the test reg-
ulations are met.
The EBCM performs system self–diagnostics and can de-
tect and often isolate system malfunctions. When it de-
tects a malfunction, the EBCM sets a DTC that represents
the malfunction, turns ON the ABS and/or the EBD indica-
tors in most instances, and may disable the ABS and/or
the EBD functions as necessary for the duration of the igni-
tion cycle.
Once each ignition cycle, the EBCM performs an automat-
ic test when the vehicle speed > 6 km/h and the brake ped-
al is not actuated or when the vehicle speed > 15 km/h and
the brake pedal is actuated. In the course of this test, the
system cycles each valve solenoid and the pump motor,
along with the necessary relays, to check component op-
eration. If the EBCM detects any malfunctions, it will set
a DTC as described above.
DISPLAYING DTCS
Tools Required
Scan Tool
DTCs can be read through the use of the scan tool.
CLEARING DTCS
Tools Required
Scan Tool
The diagnostic trouble codes (DTCs) in the electronic
brake control module (EBCM) memory are erased:S Use the scan tool ”Clear DTCs” selection.
The method is detailed below. Be sure to verify proper sys-
tem operation and absence of DTCs when the clearing
procedure is completed.
The EBCM will not permit DTC clearing until all DTCs have
been displayed. Also, DTCs cannot be cleared by discon-
necting the EBCM, disconnecting the battery cables, or
turning the ignition switch to LOCK.
Scan Tool Method
The scan tool can clear ABS system DTCs using the mass
storage cartridge.
1. Install the scan tool and the mass storage cartridge.
2. Select ”Fault Memory.”
3. Select ”Clear Fault Memory.”
Clearing the fault memory cannot reset a valve relay which
was shut down when the fault was recognized. Changes
are possible only after the fault has been eliminated and
the next ignition cycle has begun.
INTERMITTENTS AND POOR
CONNECTIONS
As with most electronic systems, intermittent malfunctions
may be difficult to diagnose accurately. The following is a
method to try to isolate an intermittent malfunction, espe-
cially in wheel speed circuitry.
If an ABS malfunction occurs, the ABS indicator will illumi-
nate during the ignition cycle in which the malfunction was
detected. If it is an intermittent problem which seems to
have corrected itself (ABS indicator off), a history DTC will
be stored. Also stored will be the history data of the DTC
at the time the malfunction occurred. Use the scan tool
modular diagnostic system to read ABS history data.
Most intermittents are caused by faulty electrical connec-
tions or wiring, although a sticking relay or solenoid can oc-
casionally be at fault.

ANTILOCK BRAKE SYSTEM 4F – 23
DAEWOO V–121 BL4
J3B14F05
Left Front
Wheel Speed
Sensor
EBCM
LH BLU BRN1
2
76
DIAGNOSTIC TROUBLE CODE (DTC) C0035
LEFT FRONT WHEEL SPEED SENSOR CIRCUIT
MALFUNCTION
Circuit Description
The toothed wheel generates a voltage pulse as it moves
past the sensor. Each tooth–gap–tooth series on the
wheel generates the pulses. The electronic brake control
module (EBCM) uses the frequency of these pulses to de-
termine the wheel speed. The voltage generated depends
on the air gap between the sensor and the toothed wheel,
and on the wheel speed.
Diagnosis
This procedure checks for a malfunctioning wheel speed
sensor, a short to ground or to voltage in the wiring, or a
contact problem in a connector.
Cause(s)
S The wheel speed sensor is defective or discon-
nected.
S There is a problem in the wiring.
S There is a problem with a connector.
S There is a problem in the toothed ring.
S Wrong installed WSS.
S Wrong sensor signal.
S Signal noise via WSS.
Fail Action
ABS action is disabled, and the ABS warning lamp is ON.
EBD is enabled. (Refer to the EBD failure matrix in this
section).
Test Description
The number(s) below refer to step(s) on the diagnostic
table.1. This step begins an examination for a defective
wheel speed sensor.
6. This step tests the wiring for a short to voltage.
8. This step tests the wiring for a short to ground.
10. This step tests for an open or a high resistance in
the wiring.
Diagnostic Aids
Be sure that the speed sensor wiring is properly routed and
retained. This will help to prevent false signals due to the
pickup of electrical noise.
It is very important to perform a thorough inspection of the
wiring and the connectors. Failure to inspect the wiring
and the connectors carefully and completely may result in
misdiagnosis, causing part replacement with the reap-
pearance of the malfunction.
You can use the scan tool to monitor wheel speeds during
a road test. Watch the wheel speeds being displayed on
the scan tool to see if any of the readings is unusual, such
as one sensor varying in speed from the other three, a sig-
nal going intermittently high or low, etc. If this does not
identify the intermittent, wet the speed sensor harness on
the underside of the vehicle and perform a road test, moni-
toring the wheel speeds with the scan tool.
Important : If the WSS signal fault input to the EBCM, the
ABS warning lamp turns on. As if a sensor signal fault can
be removed by the scan tool, the ABS warning lamp
doesn’t turn off. In order to turn ABS warning lamp off, you
should driver a car up to 12 km/h.

4F – 24IANTILOCK BRAKE SYSTEM
DAEWOO V–121 BL4
DTC C0035 – Left Front 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 front 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 6 at the harness EBCM connector.
3. Measure the resistance to ground from termi-
nal 7 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 6 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 7 at
the harness EBCM connector and the harness
wheel speed sensor connector terminal con-
nected to the ORN wire.
Is the resistance on either circuit within the specified
value?> 5 WGo to Step 11Go to Step 12

ANTILOCK BRAKE SYSTEM 4F – 25
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
11Repair the open or high resistance in the affected cir-
cuit as required.
Is the repair complete?–System OK–
12Replace the ABS unit.
Is the repair complete?–System OK–

4F – 26IANTILOCK BRAKE SYSTEM
DAEWOO V–121 BL4
J3B14F06
Right Front
Wheel Speed
Sensor
EBCM
PPL
GRYYEL
C111
WHT 1
12
2
4 5
DIAGNOSTIC TROUBLE CODE (DTC) C0040
RIGHT FRONT WHEEL SPEED SENSOR CIRCUIT
MALFUNCTION
Circuit Description
The toothed wheel generates a voltage pulse as it moves
past the sensor. Each tooth–gap–tooth series on the
wheel generates the pulses. The electronic brake control
module (EBCM) uses the frequency of these pulses to de-
termine the wheel speed. The voltage generated depends
on the air gap between the sensor and the toothed wheel,
and on the wheel speed.
Diagnosis
This procedure checks for a malfunctioning wheel speed
sensor, a short to ground or to voltage in the wiring, or a
contact problem in a connector.
Cause(s)
S The wheel speed sensor is defective or discon-
nected.
S There is a problem in the wiring.
S There is a problem with a connector.
S There is a problem in the toothed ring.
S Wrong installed WSS.
S Wrong sensor signal.
S Signal noise via WSS.
Fail Action
ABS action is disabled, and the ABS warning lamp is ON.
EBD is enabled. (Refer to the EBD failure matrix in this
section)
Test Description
The number(s) below refer to step(s) on the diagnostic
table.1. This step begins an examination for a defective
wheel speed sensor.
6. This step tests the wiring for a short to voltage.
8. This step tests the wiring for a short to ground.
10. This step tests for an open or high resistance in the
wiring.
Diagnostic Aids
Be sure that the speed sensor wiring is properly routed and
retained. This will help to prevent false signals due to the
pickup of electrical noise.
It is very important to perform a thorough inspection of the
wiring and the connectors. Failure to inspect the wiring
and the connectors carefully and completely may result in
misdiagnosis, causing part replacement with the reap-
pearance of the malfunction.
You can use the scan tool to monitor wheel speeds during
a road test. Watch the wheel speeds being displayed on
the scan tool to see if any of the readings is unusual, such
as one sensor varying in speed from the other three, a sig-
nal going intermittently high or low, etc. If this does not
identify the intermittent, wet the speed sensor harness on
the underside of the vehicle and perform a road test, moni-
toring the wheel speeds with the scan tool.
Important : If the WSS signal fault input to the EBCM, the
ABS warning lamp turns on. As if a sensor signal fault can
be removed by the scan tool, the ABS warning lamp
doesn’t turn off. In order to turn ABS warning lamp off, you
should drive a car up to 12 km/h.

ANTILOCK BRAKE SYSTEM 4F – 27
DAEWOO V–121 BL4
DTC C0040 – Right Front 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 right front 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 4 at the harness EBCM connector.
3. Measure the resistance to ground from termi-
nal 5 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 4 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 5 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

4F – 28IANTILOCK BRAKE SYSTEM
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
11Repair the open or high resistance in the affected cir-
cuit as required.
Is the repair complete?–System OK–
12Replace the ABS unit.
Is the repair complete?–System OK–

ANTILOCK BRAKE SYSTEM 4F – 29
DAEWOO V–121 BL4
J3B14F07
Left Rear
Wheel Speed
Sensor EBCM
RED
DK BLUBLK
GRYBLK
C302 C110
WHT5 8
14 9
43
2
DIAGNOSTIC TROUBLE CODE (DTC) C0045
LEFT REAR WHEEL SPEED SENSOR CIRCUIT
MALFUNCTION
Circuit Description
The toothed wheel generates a voltage pulse as it moves
past the sensor. Each tooth–gap–tooth series on the
wheel generates the pulses. The electronic brake control
module (EBCM) uses the frequency of these pulses to de-
termine the wheel speed. The voltage generated depends
on the air gap between the sensor and the toothed wheel,
and on the wheel speed.
Diagnosis
This procedure checks for a malfunctioning wheel speed
sensor, a short to ground or to voltage in the wiring, or a
contact problem in a connector.
Cause(s)
S The wheel speed sensor is defective or discon-
nected.
S There is a problem in the wiring.
S There is a problem with a connector.
S There is a problem in the toothed ring.
S Wrong installed WSS.
S Wrong sensor signal.
S Signal noise via WSS.
Fail Action
ABS action is disabled, and the ABS warning lamp is ON.
EBD is enabled. (Refer to the EBD failure matrix in this
section)
Test Description
The number(s) below refer to step(s) on the diagnostic
table.1. This step begins an examination for a defective
wheel speed sensor.
6. This step tests the wiring for a short to voltage.
8. This step tests the wiring for a short to ground.
10. This step tests for an open or a high resistance in
the wiring.
Diagnostic Aids
Be sure that the speed sensor wiring is properly routed and
retained. This will help to prevent false signals due to the
pickup of electrical noise.
It is very important to perform a thorough inspection of the
wiring and the connectors. Failure to inspect the wiring
and the connectors carefully and completely may result in
misdiagnosis, causing part replacement with the reap-
pearance of the malfunction.
You can use the scan tool to monitor wheel speeds during
a road test. Watch the wheel speeds being displayed on
the scan tool to see if any of the readings is unusual, such
as one sensor varying in speed from the other three, a sig-
nal going intermittently high or low, etc. If this does not
identify the intermittent, wet the speed sensor harness on
the underside of the vehicle and perform a road test, moni-
toring wheel speeds with the scan tool.
Important : If the WSS signal fault input to the EBCM, the
ABS warning lamp turns on. As if a sensor signal fault can
be removed by the scan tool, the ABS warning lamp
doesn’t turn off. In order to turn ABS warning lamp off, you
should drive a car up to 12 km/h.