DAEWOO LACETTI 2004 Service Repair Manual

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 – 43
DAEWOO V–121 BL4
J3B14F04
60A Ef230A Ef5
2
42
C107 C105
2
C110
G106
A19
A13 A1 A14
C110 C202
C202WHT LT GRN
DK
GRN LT GRN/
BLK
BLK
DK BLUDK BLU
PPL/WHT
PPL/WHT ABS
TCS Parking
Brake
Hot at all times
RED REDRED/WHT
Ignition
Switch
RED
RED
I/P Cluster
EBCM8
20
22 2216 41
1211
18 1621
1
C107
10A F410AF11
32 31
43
6 62 C201
C201 C201C201
C110 C202
Hot in Run and Start
30
4
1711
C202
15
B15
DLC
(Data Link
Connector)12
G106
BLK/WHTOil Feeding
Connector
”2” Ter.
BRNBRN BRN
BRN PNK PNK PNK
19J1
59B1
ONStart Lock
Acc
IG1
19
DIAGNOSTIC TROUBLE CODE (DTC) C0110
PUMP MOTOR CIRCUIT MALFUNCTION
Circuit Description
When the electronic brake control module (EBCM)
grounds the pump motor relay, it closes and provides bat-
tery voltage to the pump motor if the valve relay is closed.
The EBCM senses the voltage applied to the pump motor
to verify motor operation.
Diagnosis
This DTC sets when the EBCM detects B+ without motor
relay activation or if the EBCM does not detect B+ after
motor relay activation.
Cause(s)
S There is a faulty terminal in pump motor connector.
S There is a faulty terminal in EBCM connector.
S There is a problem in the ABS wiring harness.
S There is high resistance in the chassis ground.
S The EBCM is defective.S There is a problem in the wiring from pump motor
connector to the motor.
Fail Action
ABS is disabled, and the ABS warning lamp is ON. EBD
is disabled.
Test Description
The number(s) below refer to step(s) on the diagnostic
table.
1. This step checks for connector damage.
3. This step checks for a poor ground connection.
7. This step checks for a possible problem with the
motor connector at the ABS unit.
Diagnostic Aids
It is very important to perform a thorough inspection of the
wiring and the connectors. Failure to do so may result in
misdiagnosis, causing part replacement with reappear-
ance of the malfunction.

4F – 44IANTILOCK BRAKE SYSTEM
DAEWOO V–121 BL4
DTC C0110 – Pump Motor Circuit Malfunction
StepActionValue(s)YesNo
11. Disconnect connector from the EBCM.
2. Examine terminal 16 on the harness connector
and on the EBCM connector.
Is the terminal damaged or corroded?–Go to Step 2Go to Step 3
2Repair or replace the terminal, the connector, the
wiring harness, or the EBCM as required.
Is the repair complete?–System OK–
3Measure the resistance from terminal 16 of the har-
ness connector to a good chassis ground.
Is the resistance equal to the specified value?
0 WGo to Step 7Go to Step 4
4Measure the resistance at the chassis ground con-
nection G106.
Is the resistance equal to the specified value?
0 WGo to Step 6Go to Step 5
5Repair the connection at chassis ground G106.
Is the repair complete?–System OK–
6Repair the open or the high resistance in the harness
between terminal 16 of connector J1 and the ground
lug, or replace the ABS wiring harness.
Is the repair complete?–System OK–
71. Remove the ABS unit from the vehicle.
2. Disconnect connector J2 and examine the ter-
minals.
Is there any sign of damage or corrosion that would
prevent a good ground contact?–Go to Step 8Go to Step 9
8Repair or replace the defective terminal, connector,
or ABS unit as required.
Is the repair complete?–System OK–
9Replace the ABS unit.
Is the repair complete?–System OK–

ANTILOCK BRAKE SYSTEM 4F – 45
DAEWOO V–121 BL4
J3B14F04
60A Ef230A Ef5
2
42
C107 C105
2
C110
G106
A19
A13 A1 A14
C110 C202
C202WHT LT GRN
DK
GRN LT GRN/
BLK
BLK
DK BLUDK BLU
PPL/WHT
PPL/WHT ABS
TCS Parking
Brake
Hot at all times
RED REDRED/WHT
Ignition
Switch
RED
RED
I/P Cluster
EBCM8
20
22 2216 41
1211
18 1621
1
C107
10A F410AF11
32 31
43
6 62 C201
C201 C201C201
C110 C202
Hot in Run and Start
30
4
1711
C202
15
B15
DLC
(Data Link
Connector)12
G106
BLK/WHTOil Feeding
Connector
”2” Ter.
BRNBRN BRN
BRN PNK PNK PNK
19J1
59B1
ONStart Lock
Acc
IG1
19
DIAGNOSTIC TROUBLE CODE (DTC) C0121
VALVE RELAY CIRCUIT MALFUNCTION
Circuit Description
When the ABS is active, the valve relay provides voltage
to actuate the solenoid valves. The valves do not use this
voltage unless the ABS control module provides the
ground for each solenoid coil.
DTC C0121 will set if the valve relay voltage is low or if the
relay supply line is at 12 volts when the ABS control mod-
ule is not requesting it. This DTC will also set if the ABS
control module detects three or more solenoid valve cir-
cuits are open or shorted during the self–test.
Diagnosis
This procedure checks whether there is a poor ground
connection for the electronic brake control module
(EBCM).Cause(s)
S A connector terminal is corroded.
S The wiring harness is damaged.
S The ground terminal is not conducting properly.
S The EBCM is defective.
Fail Action
ABS/EBD is disabled, and the ABS / EBD warning lamp
is turned ON for the remainder of the ignition cycle. If the
failure is intermittent, the control module will enable the
system at the next ignition cycle and set a history DTC
C0121.
Diagnostic Aids
It is very important to perform a thorough inspection of the
wiring and the connectors. Failure to do so may result in
misdiagnosis, causing part replacement with reappear-
ance of the malfunction.

4F – 46IANTILOCK BRAKE SYSTEM
DAEWOO V–121 BL4
DTC C0121 – Valve Relay Circuit Malfunction
StepActionValue(s)YesNo
11. Use a scan tool to clear all DTCs.
2. Road test the vehicle.
Does DTC C0121 set again?–Go to Step 3Go to Step 2
21. Check all system wiring harness connectors
and terminals, especially the EBCM, for any
problem that could cause an intermittent condi-
tion.
2. Repair any intermittent problem found.
Is the repair complete?–System OK–
31. Disconnect ABS harness connector J1 from
the EBCM.
2. Examine terminal 19 on the harness connector
and the EBCM connector.
Is there damage or corrosion at terminal 19?–Go to Step 4Go to Step 5
4Repair the terminal or the connector, or replace the
ABS harness or ABS unit as required.
Is the resistance equal to the specified value?–System OK–
5Measure the resistance from terminal 19 of the har-
ness connector J1 to a good chassis ground.
Is the resistance equal to the specified value?
0 WGo to Step 6Go to Step 7
6Replace the ABS unit.
Is the repair complete?–System OK–
7Measure the resistance from terminal 19 of the har-
ness connector J1 to the ground lug at G106.
Is the resistance equal to the specified value?
0 WGo to Step 8Go to Step 9
8Repair the chassis connection at the ground lug.
Is the repair complete?–System OK–
9Repair the open or the high resistance in the ABS
harness, or replace the harness as required.
Is the repair complete?–System OK–

ANTILOCK BRAKE SYSTEM 4F – 47
DAEWOO V–121 BL4
J3B14F10
EBCM
ORN/
BLK
LT BLULT B L U
BLK/ WHT
C201 C202
141
40
19
61
G1062
4
15A Ef13
6
C10211
S30114
C201C110
76
C202 11
DIAGNOSTIC TROUBLE CODE (DTC) C0161
ABS BRAKE SWITCH CIRCUIT MALFUNCTION
Circuit Description
When the brake pedal is depressed, the contacts on the
brake light switch close to illuminate the brake lights. Bat-
tery voltage is also applied to terminal 14 of the electronic
brake control module (EBCM), which signals the ABS con-
troller that the brakes are applied and ABS may be need-
ed. Without this, signals from a wheel speed sensor that
may indicate need for ABS intervention are questionable.
When the brake pedal is not depressed, the EBCM termi-
nal 14 is grounded through the brake lights.
Diagnosis
This procedure will check whether there is no output or
constant output from the brake light switch and will deter-
mine the cause as a faulty switch or a problem in the cir-
cuitry.
Cause(s)
S The ground connection or the positive connection at
the EBCM has failed.
S There is an open, short to ground, or short to posi-
tive in the vehicle wiring.S The brake light switch has failed.
Fail Action
The system records a DTC C0161. ABS and EBD opera-
tion is enabled and ABS / EBD warning lamp don’t turn on.
Test Description
The number(s) below refer to step(s) on the diagnostic
table.
1. This simple test will isolate the problem to the fuse–
brake light switch–splice 301 area or the splice
301–EBCM area.
3. This is the first step in identifying an open, a short
to ground, a short to voltage, or a faulty brake light
switch.
11. This step begins the process of finding an open, a
defective connector, or a faulty EBCM.
Diagnostic Aids
Inspect wiring and connectors carefully and thoroughly.
Failure to do so could result in misdiagnosis, causing part
replacement with reappearance of the malfunction.

4F – 48IANTILOCK BRAKE SYSTEM
DAEWOO V–121 BL4
DTC C0161 – ABS Brake Switch Circuit Malfunction
StepActionValue(s)YesNo
1Step on the brake pedal.
Do the brake lights come on at all?–Go to Step 3Go to Step 2
2Remove your foot from the brake pedal.
Do the lights stay on continuously?–Go to Step 8Go to Step 11
3Check fuse EF13 in the engine compartment fuse
block.
Is fuse EF13 blown?–Go to Step 4Go to Step 6
41. Replace fuse EF13.
2. Check the new fuse.
Does the new fuse blow?–Go to Step 5Go to Step 7
51. Repair the short to ground in the brake light
circuitry.
2. Install a new fuse EF13.
Is the repair complete?–System OK–
6Repair the open in the brake light switch circuit ORN/
BLK from terminal 6 of connector C102 at the engine
fuse block to the brake light switch and circuit LT
BLU from terminal 11 of splice S301.
Is the repair complete?–System OK–
7Check for functioning of the brake lights and the ABS
system.
Is the repair complete?–System OK–
8Check the brake light switch on the brake pedal.
Is the switch faulty?–Go to Step 9Go to Step 10
9Repair the brake light switch.
Is the repair complete?–System OK–
10Repair the short to positive in the circuit YEL be-
tween the brake light switch, splice S301, the brake
lights, the center high–mounted stoplamp, and the
ABS wiring harness connector at the EBCM terminal
14.
Is the repair complete?–System OK–
111. Disconnect the EBCM connector.
2. Use a digital voltmeter (DVM) to measure volt-
age between pins 14 and 19 of the ABS har-
ness connector at the EBCM.
3. Have an assistant step on the brake pedal.
Does the DVM indicate the specified value?11–14 vGo to Step 13Go to Step 12

ANTILOCK BRAKE SYSTEM 4F – 49
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
121. Examine the connection between the ABS har-
ness connector and the EBCM connector ter-
minals 14 and 19.
2. Examine the connection at terminal 1 of con-
nector C110.
3. Examine the wiring of circuit LT BLU between
splice S301 and terminal 14 of the ABS EBCM
connector for an open condition.
4. Examine the wiring between ground G106 and
terminal 19 of the ABS EBCM connector.
5. Repair the broken wire or the defective connec-
tor terminal, or replace the connector, the wir-
ing harness as required.
Is the repair complete?–System OK–
13Check the interface between the ABS EBCM con-
nector and the EBCM.
Check the interface between the ABS EBCM con-
nector and the EBCM.–Go to Step 14Go to Step 15
14Repair the connector or replace the wiring harness
or the ABS unit as required.
Is the repair complete?–System OK–
15Replace the ABS unit.
Is the repair complete?–System OK–