2004 DAEWOO NUBIRA lock

ANTILOCK BRAKE SYSTEM 4F – 63
DAEWOO V–121 BL4
FRONT WHEEL SPEED SENSOR
JUMPER HARNESS
(Left–Hand Drive Shown, Right–Hand Drive
Similar)
Removal Procedure
1. Disconnect the negative battery cable.
2. Disconnect connector from the EBCM.
3. Remove the appropriate terminals from connector:
S Right–side – terminals 4 (WHT) and 5 (GRY).
S Left–side – terminals 6 (BRN) and 7 (LT BLU).
4. Both speed sensor harnesses break out of the ABS
wiring harness just beyond the ABS connector. The
right–side speed sensor harness crosses the top of
the fire wall to the right–side fender area. The left–
side speed sensor harness goes directly to the left–
side fender area.
5. Free the speed sensor harness from the wiring har-
ness.
6. Remove the front wheel speed sensor electrical
connector from the retaining clamps and disconnect
the harness from the sensor connector.
Installation Procedure
1. Install the front wheel speed sensor jumper har-
ness.
2. Connect the front wheel speed sensor electrical
connector and secure it into the clamps.
3. Replace the jumper harness into the wiring har-
ness.
4. Insert the terminals into connector as they had
been removed:
S Right–side – terminals 4 (WHT) and 5 (GRY).
S Left–side – terminals 6 (BRN) and 7 (LT BLU).
5. Connect EBCM connector.
6. Connect the negative battery cable.

4F – 64IANTILOCK BRAKE SYSTEM
DAEWOO V–121 BL4
REAR WHEEL SPEED SENSOR
Removal Procedure
1. Disconnect the negative battery cable.
2. Raise and suitably support the vehicle.
3. Disconnect the rear wheel speed sensor electrical
connector.
4. Remove the rear hub unit from the knuckle assem-
bly, because the wheel speed sensor is not service-
able separately.
Installation Procedure
1. Install the rear hub unit to the knuckle assembly.
Tighten
Tighten the rear hub unit to the knuckle assembly to
65 NSm (48 lb–ft).
2. Connect the rear wheel speed sensor electrical
connector.

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.

4F – 66IANTILOCK BRAKE SYSTEM
DAEWOO V–121 BL4
1. Check Valve
2. Inlet Valve
3. Outlet Valve
4. Pump
5. Accumulator
6. Damper7. Pump Motor
8. Hydraulic Circuit 2
9. Hydraulic Circuit 1
10. Master Cylinder
11. Master Cylinder Reservoir
ANTILOCK BRAKING MODE – APPLY
If a wheel speed sensor detects a wheel locking up, the
electronic brake control module (EBCM) closes the nor-
mally open inlet valve for the brake on that wheel to pre-
vent adding more hydraulic pressure to that brake.

ANTILOCK BRAKE SYSTEM 4F – 67
DAEWOO V–121 BL4
ANTILOCK BRAKING MODE – HOLD
The illustration shows this for the right front brake.

4F – 68IANTILOCK BRAKE SYSTEM
DAEWOO V–121 BL4
ANTILOCK BRAKING MODE –
RELEASE
If the wheel locking tendency continues, the EBCM re-
leases the hydraulic pressure at that brake by opening the
outlet valve for that wheel.

ANTILOCK BRAKE SYSTEM 4F – 69
DAEWOO V–121 BL4
EBD (ELECTRONIC BRAKE FORCE
DISTRIBUTION) SYSTEM
As an add–on logic to the ABS base algorithm, EBD works
in a range in which the intervention thresholds for ABS
control are not reached yet.
EBD ensures that the rear wheels are sensitively moni-
tored for slip with respect to the front axle. If slip is de-
tected, the inlet valves for the rear wheels are switched to
pressure hold to prevent a further increase in pressure at
the rear–wheel breaks, thus electronically reproducing a
pressure–reduction function at the rear–wheel brakes.
THE BENEFITS OF EBD
S Elimination of conventional proportioning valve.
S EBD utilizes the existing rear axle wheel speed
sensor to monitor rear wheel slip.
S Based on many variables in algorithm a pressure
hold, increase and/or decrease pulsetrain may be
triggered at the rear wheels insuring vehicle stabil-
ity.
S Vehicle approaches the ideal brake force distribu-
tion. (front to rear)
S Constant brake force distribution during vehicle life-
time.
S EBD function is monitored via ABS safety logic.
(conventional proportioning valves are not monitor-
able)
S ”Keep alive” function.

4F – 70IANTILOCK BRAKE SYSTEM
DAEWOO V–121 BL4
ELECTRONIC BRAKE–FORCE DISTRIBUTION (EBD)
FAILURE MATRIX