2004 DAEWOO LACETTI Section 6

4F – 32IANTILOCK BRAKE SYSTEM
DAEWOO V–121 BL4
J3B14F08
Right Rear
Wheel Speed
Sensor EBCM
BRN
BRN
GRYC302 C110
WHT WHT
WHT1
110
1 3
3
2
2
DIAGNOSTIC TROUBLE CODE (DTC) C0050
RIGHT 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 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.

ANTILOCK BRAKE SYSTEM 4F – 61
DAEWOO V–121 BL4
BLEEDING SYSTEM
Replacement modulators are shipped already filled and
bled. In normal procedures requiring removal of the modu-
lator, such as to replace the EBCM, air will not enter the
modulator, and normal bleeding will be all that is needed.
For this procedure, refer to Section 4A, Hydraulic Brakes.
If air enters the hydraulic modulator, or if an unfilled modu-
lator is installed, use the brake bleeding program in the
scan tool to bleed the modulator. Manual bleeding of the
hydraulic modulator is not possible.
ABS 5.3 ASSEMBLY
(Left–Hand Drive Shown, Right–Hand Drive
Similar)
Removal Procedure
1. Disconnect the negative battery cable.
2. Disconnect the 31–pin ABS wiring harness connec-
tor from its socket on the EBCM.
3. Cover the connector and the socket with shop
cloths to protect them from brake fluid.
Notice : Take care not to allow air into the hydraulic unit
or into the brake pipes from the master cylinder. If air gets
into the hydraulic unit, it will require a bleeding procedure
using a scan tool programmed for the ABS 5.3 system. As
long as no air enters the hydraulic unit, a simple bleeding
procedure is all the system will require.
4. Remove the brake pipes from the hydraulic unit. It
may be necessary to loosen the brake pipe nuts on
the master cylinder to allow for moving those pipes
out of the way.
5. Loosen the mounting nuts on the hydraulic unit.
6. Move the brake pipes aside far enough to allow for
lifting the ABS 5.3 unit out of the mounting bracket.
7. Tighten the brake pipe nuts on the master cylinder
to avoid leaking brake fluid.
8. Cap the brake pipes.
Installation Procedure
1. Insert the ABS 5.3 hydraulic unit into its mounting
bracket and install the nuts.
Tighten
Tighten the ABS 5.3 mounting nuts to 15 NSm (11 lb–
ft).
2. Remove the screw plugs and install all of the hy-
draulic brake pipes.
Tighten
Tighten the brake pipe nuts to 22 NSm (16 lb–ft).
3. Connect the 31–pin wiring harness connector J1.
4. Connect the negative battery cable.
5. Bleed the hydraulic system. Refer to Section 4A,
Hydraulic Brakes.

4F – 62IANTILOCK BRAKE SYSTEM
DAEWOO V–121 BL4
FRONT WHEEL SPEED SENSOR
Removal Procedure
1. Disconnect the negative battery cable.
2. Disconnect the front wheel speed sensor electrical
connector.
3. Raise and suitably support the vehicle.
4. Remove the wheel. Refer to Section 2E, Tires and
Wheels.
5. Turn the steering wheel to expose the speed sen-
sor. It is located at the rear of the steering knuckle
near the tie rod end.
6. Remove the bolt and the front wheel speed sensor
from the steering knuckle.
7. Free the feedthrough grommet for the speed sen-
sor harness and the hydraulic pipe from the strut
tower. Remove the speed sensor harness from it so
that the connector can pass through the hole in the
strut tower.
8. Free the sensor harness from the grommet holders
and the clamps and pull it through the fender.
Installation Procedure
1. Install the front wheel speed sensor to the steering
knuckle. Secure it with the bolt.
Tighten
Tighten the front wheel speed sensor bolt to 8 NSm
(71 lb–in).
2. Feed the sensor harness into the engine compart-
ment, insert it into the grommet, and secure the
grommet into the hole in the strut tower.
3. Secure the harness into the grommet holders and
the clamps under the fender.
4. Install the wheel. Refer to Section 2E, Tires and
Wheels.
5. Lower the vehicle.
6. Connect the front wheel speed sensor electrical
connector.
7. Connect the negative battery cable.

ANTILOCK BRAKE SYSTEM 4F – 65
DAEWOO V–121 BL4
GENERAL DESCRIPTION AND SYSTEM
OPERATION
BASIC KNOWLEDGE REQUIRED
Before using this section, it is important that you have a ba-
sic knowledge of the following items. Without this knowl-
edge, it will be difficult to use the diagnostic procedures
contained in this section.
S Basic Electrical Circuits : You should understand
the basic theory of electricity and know the mean-
ing of voltage, current (amps), and resistance
(ohms). You should understand what happens in a
circuit with an open or shorted wire. You should be
able to read and understand a wiring diagram.
S Use of Circuit Testing Tools : You should know how
to use a test light and how to bypass components
to test circuits using fused jumper wires. You should
be familiar with a digital multimeter. You should be
able to measure voltage, resistance, and current,
and be familiar with the controls and how to use
them correctly.
ABS SYSTEM COMPONENTS
The ABS 5.3 Antilock Braking System (ABS) consists of
a conventional hydraulic brake system plus antilock com-
ponents. The conventional brake system includes a vacu-
um booster, master cylinder, front disc brakes, rear lead-
ing/trailing drum brakes, interconnecting hydraulic brake
pipes and hoses, brake fluid level sensor and the BRAKE
indicator.
The ABS components include a hydraulic unit, an elec-
tronic brake control module (EBCM), two system fuses,
four wheel speed sensors (one at each wheel), intercon-
necting wiring, the ABS indicator, the EBD indicator (which
is connected to the parking lamp) and the rear disk brakes.
See “ABS Component Locator” in this section for the gen-
eral layout of this system.
The hydraulic unit with the attached EBCM is located be-
tween the surge tank and the fire wall on the left side of the
vehicle.
The basic hydraulic unit configuration consists of hydraulic
check valves, two solenoid valves for each wheel, a hy-
draulic pump, two accumulators, and two damper. The hy-
draulic unit controls hydraulic pressure to the front calipers
and rear wheel cylinders by modulating hydraulic pressure
to prevent wheel lockup.
Nothing in the hydraulic unit or the EBCM is serviceable.
In the event of any failure, the entire ABS unit with at-
tached EBCM must be replaced. For more information, re-
fer to ”Base Braking Mode” and ”Antilock Braking Mode”
in this section.
BASE BRAKING MODE
The baseline braking mode of the ABS 5.3 system used
in this vehicle is a diagonal split system. In this system,
one master cylinder circuit supplies pressure to the right
front and the left rear brakes; the other circuit supplies
pressure to the left front and the right rear brakes. All
valves in the hydraulic modulator are in their normal, non–
energized positions as shown in the drawings found in
”ABS System Components” in this section.

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.

SECTION : 4G
PARKING BRAKE
TABLE OF CONTENTS
SPECIFICATIONS4G–1 . . . . . . . . . . . . . . . . . . . . . . . . . .
Fastener Tightening Specifications 4G–1. . . . . . . . . .
MAINTENANCE AND REPAIR4G–2 . . . . . . . . . . . . . . .
ON–VEHICLE SERVICE 4G–2. . . . . . . . . . . . . . . . . . . . .
Parking Brake Adjustment Rear Drum Brakes 4G–2.
Parking Brake Adjustment Rear Disc Brakes 4G–2. . Parking Brake Lever 4G–3. . . . . . . . . . . . . . . . . . . . . . .
Parking Brake Cable 4G–5. . . . . . . . . . . . . . . . . . . . . . .
Parking Brake Handle 4G–8. . . . . . . . . . . . . . . . . . . . . .
GENERAL DESCRIPTION AND SYSTEM
OPERATION4G–9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Parking Brake 4G–9. . . . . . . . . . . . . . . . . . . . . . . . . . . .
SPECIFICATIONS
FASTENER TIGHTENING SPECIFICATIONS
ApplicationNSmLb–FtLb–In
Parking Brake Cable–to–Underbody Side
Bracket bolts6–53
Parking Brake Lever Assembly–to–Vehicle
Underbody Bolts2216–
Parking Brake Switch–to–Parking Brake Le-
ver Screw4–35
Rear Brake Drum Detent Screw4–35

4G – 2IPARKING BRAKE
DAEWOO V–121 BL4
MAINTENANCE AND REPAIR
ON–VEHICLE SERVICE
PARKING BRAKE ADJUSTMENT
REAR DRUM BRAKES
Adjustment Procedure
1. Adjust the rear brakes. Refer to Section 4E1, Rear
Disc Brakes.
2. Release the parking brake.
3. Raise and suitably support the vehicle.
4. Check the parking brake cables for free movement.
5. Lower the vehicle
6. Remove the parking brake/gearshift console hood.
Refer to Section 9G, Interior Trim.
7. Partially raise the vehicle.
8. Turn the self–locking nut on the parking brake lever
assembly until the wheels are difficult to turn.
9. Back off the nut until the rear wheels are just free to
turn.
10. Lower the vehicle
11. Install the parking brake/gearshift console hood.
Refer to Section 9G, Interior Trim.
PARKING BRAKE ADJUSTMENT
REAR DISC BRAKES
Adjustment Procedure
1. Release the parking brake.
2. Raise and suitably support the vehicle.
3. Remove the rear wheels. Refer to Section 2E, Tires
and Wheels.
4. Remove the caliper and rotor assemblies. Refer to
Section 4E1, Rear Disc Brakes.
5. Remove the brake rotors on each side of the ve-
hicle. Refer to Section 4E1, Rear Disc Brakes.
6. Disconnect the parking brake cable from the back-
plate operating lever on each side of the vehicle.

PARKING BRAKE 4G – 3
DAEWOO V–121 BL4
7. Inspect and replace any parts of doubtful strength
or quality. This can be shown by discoloration from
heat or stress.
8. Using a vernier caliper, adjust the shoe assembly to
167.6 to 167.8 mm (6.60 to 6.61 inches) by turning
the adjuster nut clockwise to increase the diameter.
Measure the shoe assembly diameter as closely as
possible to the center of the lining material.
9. Inspect and install the rotors and calipers. Refer to
Section 4E1, Rear Disc Brakes.
10. Install the parking brake cable to the backplate le-
ver on each side of the vehicle.
11. In the vehicle cabin, pull on the parking brake han-
dle. Stop after hearing two clicks.
12. Turn the rear wheel by hand until the wheel begins
to drag.
13. Release the parking brake.
14. Turn the rear wheel by hand to check the drag. Re-
adjust the cable, if necessary.
15. Repeat the process for the other rear wheel.
16. Lower the vehicle.
PARKING BRAKE LEVER
Removal Procedure
1. Release the parking brake.
2. Remove the parking brake/gearshift console hood.
Refer to Section 9G, Interior Trim.
3. Measure the thread length from the end of the pull
rod to the hex nut.
4. Remove the hex nut.
5. Remove the parking brake warning lamp switch.
Notice : The parking brake switch should be replaced if
the BRAKE warning light in the instrument panel cluster
did not glow when the parking brake was applied with the
ignition switch ON.