2004 DAEWOO LACETTI driver

MASTER CYLINDER 4B – 7
DAEWOO V–121 BL4
UNIT REPAIR
MASTER CYLINDER OVERHAUL
Disassembly Procedure
1. Remove the master cylinder. Refer to ”Master Cyl-
inder Assembly” in this section.
2. Remove the brake fluid reservoir. Refer to ”Brake
Fluid Reservoir” in this section.
3. Remove the seal ring from the cylinder bore.
Notice : When removing the retaining ring, avoid damag-
ing the piston or the cylinder wall.
Important : A welding rod or its equivalent can be used in
a compensating port to keep the piston depressed.
4. Remove and discard the retaining ring from the cyl-
inder body (the non–ABS master cylinder body is
shown) using a suitable screwdriver.
5. Remove the primary piston (the ABS master cylin-
der body is shown).
6. Carefully remove the secondary piston assembly,
including the springs, from the master cylinder
bore.
Assembly Procedure
Notice : Do not use abrasives in the master cylinder bore.
Abrasives can damage the bore.
Important : Rubber parts and retaining rings must be dis-
carded and replaced with new parts.
1. Clean all parts with denatured alcohol or clean
brake fluid. Dry the parts with compressed air.
2. Inspect the master cylinder bore for scoring or cor-
rosion. If scoring or corrosion is evident, replace the
master cylinder body.
3. Lubricate the master cylinder bore (the non–ABS
master cylinder is shown) with clean brake fluid.
4. Carefully insert the secondary piston assembly bore
until the secondary piston contacts the base of the
cylinder body. Use a wood or a plastic drift, if nec-
essary.
5. Insert the primary piston.

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.

ANTILOCK BRAKE SYSTEM 4F – 59
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) C0931
OVERHEATED
DTC Description
The brake can be overheated when the TCS controls the
brake system to reduce the velocity of driving wheel. At
this moment, the EBCM calculates the brake application
time and frequency and shows the warning sign of over
heated driving wheel to the driver.Cause(s)
S EBCM show the driving wheel temperature over
400 °C.
Fail Action
TCS dose not functioning when the DTC C0931 is de-
tected.

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.

4G – 6IPARKING BRAKE
DAEWOO V–121 BL4
10. For vehicles with rear disc brakes, remove the rear
hub assembly.
11. Remove the retaining pin.
12. Remove the parking brake cable from the trailing
shoe.
13. Remove the bolts securing the parking brake cable
to the underbody clip on both the driver and pas-
senger sides of the vehicle.
14. Remove the parking brake cable from the clip near
the fuel tank strap.
15. Remove the parking brake cables from the vehicle.
Installation Procedure
1. Install the new parking brake cable (if necessary)
through the rear drum brake backing plate and at-
tach to the brake trailing shoe lever.
2. Insert the plastic sleeve in the rear drum backing
plate and press in the retaining ring. Ensure the
parking brake cable is routed correctly.

PARKING BRAKE 4G – 7
DAEWOO V–121 BL4
3. Install the rear brake drums by fastening the detent
screw.
Tighten
Tighten the rear brake drum detent screw to 4 NSm
(35 lb–in).
4. Install the parking brake cable to the trailing shoe.
5. Install the retaining pin.
6. For vehicles with rear disc brakes, install the rear
hub assembly.
7. Install the bolts securing the parking brake cable to
a bracket on both the driver and passenger sides of
the vehicle.
Tighten
Tighten the parking brake cable–to–underbody side
bracket bolts to 6 NSm (53 lb–in).
8. Install the parking brake cable to the clip near the
fuel tank strap.

5–8WELECTRICAL WIRING DIAGRAMS
1. STARTING & CHARGING SYSTEM
1) BATTERY, IGNITION SWITCH, STARTER MOTOR, GENERATOR & PNP SWITCH CIRCUIT
a. CONNECTOR INFORMATION
CONNECTOR(NO.)
(PIN NO. COLOR)
CONNECTING, WIRING HARNESSCONNECTOR POSITION
C102 (11 Pin, White)Body
Engine Fuse BlockEngine Fuse Block
C105 (4 Pin, White)Body
Engine Fuse BlockEngine Fuse Block
C106 (20 Pin, White)Engine
Engine Fuse BlockEngine Fuse Block
C108 (24 Pin, Black)Body
EngineLeft Engine Fuse Block
C201 (76 Pin, Black)I.P
I.P Fuse BlockI.P Fuse Block
C202 (89 Pin, White)I.P
BodyLeft CO–Driver Leg Room
C206 (22 Pin, White)I.P
TCMUpper Driver Leg Room
S205 (Orange)TCMUpper Driver Leg Room
G103BatteryLeft Battery
G105BatteryUnder Start Motor
G201I.PLeft I.P Fuse Block
b. CONNECTOR IDENTIFICATION SYMBOL & PIN NUMBER POSITION

5–10WELECTRICAL WIRING DIAGRAMS
2. ECM (ENGINE CONTROL MODULE) : MR – 140
1) BATTERY POWER SUPPLY, GROUND, EI SYSTEM & CKP SENSOR CIRCUIT
a. CONNECTOR INFORMATION
CONNECTOR(NO.)
(PIN NO. COLOR)
CONNECTING, WIRING HARNESSCONNECTOR POSITION
C102 (11 Pin, White)Body
Engine Fuse BlockEngine Fuse Block
C106 (20 Pin, White)Engine
Engine Fuse BlockEngine Fuse Block
C201 (76 Pin, Black)I.P
I.P Fuse BlockI.P Fuse Block
C202 (89 Pin, White)I.P
BodyLeft CO–Driver Leg Room
S101 (Black)Engine (MR–140/HV–240)Upper Transmission
G104EngineUnder Start Motor
G107Engine (MR–140/HV–240)Under Start Motor
b. CONNECTOR IDENTIFICATION SYMBOL & PIN NUMBER POSITION
J3B1P002