
POWER BOOSTER 4C – 5
DAEWOO V–121 BL4
8. Install the new vacuum hose to the booster. Refer
to ”Vacuum Hose” in this section.
9. Install the hose clamps on the vacuum hose, and
snap the vacuum hose in the revolving clip.
10. Install the pushrod pin to the brake pedal bracket
assembly and connect the clip and the spring. Re-
fer to Section 4A, Hydraulic Brakes.
11. Install the brake stoplamp switch. Refer to Section
4A, Hydraulic Brakes.

4E2 – 2IREAR DRUM BRAKES
DAEWOO V–121 BL4
lining, will not only wear the lining, but also will
make it difficult, if not impossible, to obtain proper
brake performance.
S An out–of–round drum makes accurate brake shoe
adjustment impossible and is likely to cause exces-
sive wear of other parts of the brake mechanism.
An out–of–round drum can also cause severe and
irregular tire tread wear, as well as a pulsating
brake pedal.S The extent to which a drum is worn or out of round
can be measured accurately with an inside microm-
eter fitted with the proper extension rods. When
measuring a drum for wear or the extent to which it
is out of round, take measurements from the inside
edge to the outside edge of the machined surface
at 90–degree intervals around the circumference of
the drum. When the drum exceeds the specified
out–of–round limit, refinish the drum.

ANTILOCK BRAKE SYSTEM 4F – 7
DAEWOO V–121 BL4
DIAGNOSIS
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 CIRCUIT CHECK
The Diagnostic Circuit Check is an organized approach to
identifying a problem created by an antilock brake system
(ABS) malfunction. It must be the starting point for any
ABS complaint diagnosis because it directs the service
technician to the next logical step in diagnosing the com-
plaint.
Diagnostic Process
Perform the following steps in order when servicing the
ABS/EBD system. Failure to do so may result in the loss
of important diagnostic data and may lead to difficulties
and time–consuming diagnosis procedures.1. Perform the tests of the table below.
2. Perform a road test if directed by the table.
S Test drive the vehicle while using the snapshot
feature of the scan tool.
S Perform normal acceleration, stopping, and turn-
ing maneuvers.
S If this does not reproduce the malfunction, per-
form an ABS stop on a low friction surface such
as gravel.
3. Clear the diagnostic trouble codes (DTCs) after all
system malfunctions have been corrected.
Diagnostic Circuit Check
StepActionValue(s)YesNo
11. Install the scan tool.
2. Turn ignition switch to ON.
3. Select the Data List mode.
Is the scan tool receiving data from the electronic
brake control module (EBCM) ?–Go to Step 2Go to Step 6
2Check the display.
Are there any current DTCs displayed?–Refer to the ap-
plicable DTC
tableGo to Step 3

ANTILOCK BRAKE SYSTEM 4F – 9
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
ABS INDICATOR LAMP INOPERATIVE
Circuit Description
Battery voltage is supplied to the ABS warning lamp with
the ignition switch in the ON or START positions. The
warning lamp can be activated only by the ABS control
module internally supplying ground to terminal 20 or by the
shorting bar in the ABS module connector when it is dis-
connected from the module.
Diagnosis
This procedure checks for a problem in the wiring, a faulty
ground, a voltage supply problem, a burned out indicator
lamp, or a contact problem in a connector.
Cause(s)
S A fuse has blown.
S The indicator lamp has burned out.S There is a corroded or broken connector terminal.
S There is a faulty ground connection.
S There is a broken wire in a wiring harness.
S The EBCM is faulty.
Test Description
The number(s) below refer to step(s) on the diagnostic
table.
1. This test checks for any DTCs that may cause the
ABS indicator lamp to be inoperative.
2. This test verifies an inoperative lamp condition.
3. This test checks for voltage on the lamp circuit.
4. This begins a series of tests of the circuit from the
indicator lamp to the EBCM and ground.
19. This begins a series of tests of the voltage supply
circuits that power the indicator lamp.
ABS Indicator Lamp Inoperative
StepActionValue(s)YesNo
1Install the scan tool and check for any DTCs.
Is any DTC set?–Go to the chart
for the DTCGo to Step 2
21. Turn the ignition switch to LOCK.
2. Disconnect the scan tool.
3. Turn the ignition switch to ON.
4. Observe the ABS indicator lamp.
Does the lamp illuminate for about 4 seconds, then
turn off?–Go to ”Intermit-
tents and Poor
Connections”Go to Step 3

4F – 18IANTILOCK BRAKE SYSTEM
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
ELECTRONIC BRAKE–FORCE DISTRIBUTION (EBD)
SYSTEM INDICATOR LAMP INOPERATIVE
Circuit Description
Battery voltage is supplied to the EBD warning lamp with
the ignition switch in the ON or START position. The warn-
ing lamp can be activated only by the ABS control module
internally supplying ground to terminal 21.
Diagnosis
This procedure checks for a problem in the wiring, a faulty
ground, a voltage supply problem, a burned out indicator
lamp, or a contact problem in a connector.
Cause(s)
S A fuse has blown.
S The indicator lamp has burned out.
S There is a corroded or broken connector terminal.S There is a faulty ground connection.
S There is a broken wire in a wiring harness.
S The EBCM is faulty.
Test Description
The number(s) below refer to step(s) on the diagnostic
table.
1. This test checks for any DTCs that may cause the
EBD indicator lamp to be inoperative.
2. This test verifies an inoperative lamp condition.
3. This test checks for voltage on the lamp circuit.
4. This begins a series of tests of the circuit from the
indicator lamp to the EBCM and ground.
19. This begins a series of tests of the voltage supply
circuits that power the indicator lamp.

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 – 54IANTILOCK BRAKE SYSTEM
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) C0550
ABS CONTROL MODULE INTERNAL FAULT
Circuit Description
The ABS control module performs various diagnostic
checks on itself. If it finds a problem, it sets DTC C0550.
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 EBCM is malfunctioning.
Fail Action
ABS is disabled, and the ABS warning lamp is turned ON.EBD is disabled. If the failure is intermittent, the control
module will enable the system at the next ignition cycle
and will store a history DTC C0550.
Test Description
The number(s) below refer to step(s) on the diagnostic
table.
3. This step begins the testing for a poor voltage or
ground connection.
Diagnostic Aids
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.