
GENERAL INFORMATION 0B – 15
DAEWOO V–121 BL4
GENERAL DESCRIPTION
AND SYSTEM OPERATION
GENERAL REPAIR INSTRUCTIONS
S If a floor jack is used, the following precautions are
recommended.
S Park the vehicle on level ground, block" the front
or rear wheels, set the jack against the frame, raise
the vehicle and support it with chassis stands and
then perform the service operation.
S Before performing the service operation, disconnect
the negative battery cable in order to reduce the
chance of cable damage and burning due to short–
circuiting.
S Use a cover on the body, the seats and the floor to
protect them against damage and contamination.
S Handle brake fluid and antifreeze solution with care
as they can cause paint damage.
S The use of proper tools, and the recommended es-
sential and available tools where specified, are im-
portant for efficient and reliable performance of the
service repairs.S Use genuine DAEWOO parts.
S Discard used cotter pins, gaskets, O–rings, oil
seals, lock washers and self–locking nuts. Prepare
new ones for installation. Normal function of these
parts cannot be maintained if these parts are re-
used.
S Keep the disassembled parts neatly in groups to
facilitate proper and smooth reassembly.
S Keep attaching bolts and nuts separated, as they
vary in hardness and design depending on the posi-
tion of the installation.
S Clean the parts before inspection or reassembly.
S Also clean the oil parts, etc. Use compressed air to
make certain they are free of restrictions.
S Lubricate rotating and sliding faces of parts with oil
or grease before installation.
S When necessary, use a sealer on gaskets to pre-
vent leakage.
S Carefully observe all specifications for bolt and nut
torques.
S When service operation is completed, make a final
check to be sure service was done properly and the
problem was corrected.

ENGINE ELECTRICAL 1E – 21
DAEWOO V–121 BL4
20. Remove the locking ring from the groove in the dri-
veshaft.
21. Remove the pinion stop and the drive from the dri-
veshaft.
22. If not done in the previous steps, remove the
screws that hold the solenoid assembly into the
housing, and remove the nut from the field coil con-
nector.
23. Rotate the solenoid 90 degrees and remove it along
with the return spring.

ENGINE CONTROLS 1F – 163
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
3With the engine running, operate the vehicle until the
LOOP STATUS indicates closed.
Is the Long Term Fuel Trim value above the specified
value?–30%Go to Step 4Go to Step 5
41. Turn the ignition switch ON, with the engine
OFF.
2. Review the Freeze Frame data and note the
parameters.
3. Operate the vehicle within the Freeze Frame
conditions and Conditions for Setting The DTC
as noted.
Does the Long Term Fuel Trim value above the spe-
cified value while operating under the specified con-
ditions?–30%Go to Step 21Go to Step 5
5Visually/physically check the air cleaner filter for ex-
cessive dirt or being plugged and repair as needed.
Is the repair complete?–Go to Step 21Go to Step 6
6Visually/physically check the air intake system for
collapsed or restricted and repair as needed.
Is the repair complete?–Go to Step 21Go to Step 7
7Inspect the throttle body inlet for damaged or foreign
objects which may partially block the airflow and re-
pair as needed.
Is the repair complete?–Go to Step 21Go to Step 8
81. Turn the ignition OFF.
2. Inspect the throttle bore, throttle plate and Idle
Air Control (IAC) passages for clocking and
foreign objects and repair as needed.
Is the repair complete?–Go to Step 21Go to Step 9
9Start the engine with the vehicle in park or neutral
and A/C off and note the idle quality.
Is a low or unsteady idle being experienced?–Go to Step 10Go to Step 12
10Idle the engine.
Are the IAC counts below the specified value?100Go to Step 12Go to Step 11
111. Turn the ignition OFF.
2. Disconnect the Manifold Absolute Pressure
(MAP) sensor electrical connector.
3. Start the engine.
4. Operate the vehicle in Closed Loop while moni-
toring the Long Term Fuel Trim value.
Does the Long Term Fuel Trim value increase above
the specified value?–30%Go to Step 20Go to Step 12
12Check the IAC valve performance. Refer to ”DTC
P0506 Idle Speed RPM Lower Than Desired Idle
Speed” or ”DTC P0507 Idle Speed RPM Higher
Than Desired Idle Speed” in this section and repair
as necessary.
Is the repair complete?–Go to Step 21Go to Step 13

ENGINE CONTROLS 1F – 405
DAEWOO V–121 BL4
DTC P0172 – Fuel Trim System Too Rich
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Was the check performed?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Install the scan tool to the Data Link Connector
(DLC).
2. Turn the ignition ON.
Are any component related Diagnostic Trouble
Codes (DTCs) set?–Go to applica-
ble DTC tableGo to Step 3
3With the engine running, operate the vehicle until the
LOOP STATUS indicates closed.
Is the Long Term Fuel Trim value above the specified
value?–20%Go to Step 4Go to Step 5
41. Turn the ignition switch ON, with the engine
OFF.
2. Review the Freeze Frame data and note the
parameters.
3. Operate the vehicle within the Freeze Frame
conditions and Conditions for Setting The DTC
as noted.
Does the Long Term Fuel Trim value above the spe-
cified value while operating under the specified con-
ditions?–20%Go to Step 21Go to Step 5
5Visually/physically check the air cleaner filter for ex-
cessive dirt or being plugged and repair as needed.
Is the repair complete?–Go to Step 21Go to Step 6
6Visually/physically check the air intake system for
collapsed or restricted and repair as needed.
Is the repair complete?–Go to Step 21Go to Step 7
7Inspect the throttle body inlet for damaged or foreign
objects which may partially block the airflow and re-
pair as needed.
Is the repair complete?–Go to Step 21Go to Step 8
81. Turn the ignition OFF.
2. Inspect the throttle bore, throttle plate and Idle
Air Control (IAC) passages for clocking and
foreign objects and repair as needed.
Is the repair complete?–Go to Step 21Go to Step 9
9Start the engine with the vehicle in park or neutral
and A/C off and note the idle quality.
Is a low or unsteady idle being experienced?–Go to Step 10Go to Step 12
10Idle the engine.
Are the IAC counts below the specified value?100Go to Step 12Go to Step 11

HYDRAULIC BRAKES 4A – 5
DAEWOO V–121 BL4
DIAGNOSIS
BRAKE SYSTEM TESTING
Brakes should be tested on a dry, clean, reasonably
smooth and level roadway. A true test of brake perfor-
mance cannot be made if the roadway is wet, greasy, or
covered with loose dirt whereby all tires do not grip the
road equally. Testing will also be adversely affected if the
roadway is crowned so as to throw the weight so roughly
that the wheels tend to bounce.
Test the brakes at different vehicle speeds with both light
and heavy pedal pressure; however, avoid locking the
brakes and sliding the tires. Locked brakes and sliding
tires do not indicate brake efficiency since heavily braked,
but turning, wheels will stop the vehicle in less distance
than locked brakes. More tire–to–road friction is present
with a heavily–braked, turning tire than with a sliding tire.
Because of the high deceleration capability, a firmer pedal
may be felt at higher deceleration levels.
There are three major external conditions that affect brake
performance:
S Tires having unequal contact and grip of the road
will cause unequal braking. Tires must be equally
inflated, and the tread pattern of the right and the
left tires must be approximately equal.
S Unequal loading of the vehicle can affect the brake
performance since the most heavily loaded wheels
require more braking power, and thus more braking
effort, than the others.
S Misalignment of the wheels, particularly conditions
of excessive camber and caster, will cause the
brakes to pull to one side.
To check for brake fluid leaks, hold constant foot pressure
on the pedal with the engine running at idle and the shift
lever in NEUTRAL. If the pedal gradually falls away with
the constant pressure, the hydraulic system may be leak-
ing. Perform a visual check to confirm any suspected
leaks.
Check the master cylinder fluid level. While a slight drop
in the reservoir level results from normal lining wear, an ab-
normally low level indicates a leak in the system. The hy-
draulic system may be leaking either internally or external-
ly. Refer to the procedure below to check the master
cylinder. Also, the system may appear to pass this test
while still having a slight leak. If the fluid level is normal,
check the vacuum booster pushrod length. If an incorrect
pushrod length is found, adjust or replace the rod.
Check the master cylinder using the following procedure:
S Check for a cracked master cylinder casting or
brake fluid leaking around the master cylinder.
Leaks are indicated only if there is at least one drop
of fluid. A damp condition is not abnormal.S Check for a binding pedal linkage and for an incor-
rect pushrod length. If both of these parts are in
satisfactory condition, disassemble the master cyl-
inder and check for an elongated or swollen primary
cylinder or piston seals. If swollen seals are found,
substandard or contaminated brake fluid should be
suspected. If contaminated brake fluid is found, all
the components should be disassembled and
cleaned, and all the rubber components should be
replaced. All of the pipes must also be flushed.
Improper brake fluid, or mineral oil or water in the fluid,
may cause the brake fluid to boil or cause deterioration of
the rubber components. If the primary piston cups in the
master cylinder are swollen, then the rubber parts have
deteriorated. This deterioration may also be evidenced by
swollen wheel cylinder piston seals on the drum brake
wheels.
If deterioration of rubber is evident, disassemble all the hy-
draulic parts and wash the parts with alcohol. Dry these
parts with compressed air before reassembly to keep alco-
hol out of the system. Replace all the rubber parts in the
system, including the hoses. Also, when working on the
brake mechanisms, check for fluid on the linings. If exces-
sive fluid is found, replace the linings.
If the master cylinder piston seals are in satisfactory condi-
tion, check for leaks or excessive heat conditions. If these
conditions are not found, drain the fluid, flush the master
cylinder with brake fluid, refill the master cylinder, and
bleed the system. Refer to ”Manual Bleeding the Brakes”
or”Pressure Bleeding the Brakes” in this section.
BRAKE HOSE INSPECTION
The hydraulic brake hoses should be inspected at least
twice a year. The brake hose assembly should be checked
for road hazard damage, cracks, chafing of the outer cov-
er, and for leaks or blisters. Inspect the hoses for proper
routing and mounting. A brake hose that rubs on a suspen-
sion component will wear and eventually fail. A light and
a mirror may be needed for an adequate inspection. If any
of the above conditions are observed on the brake hose,
adjust or replace the hose as necessary.
WARNING LAMP OPERATION
This brake system uses a BRAKE warning lamp located
in the instrument panel cluster. When the ignition switch
is in the START position, the BRAKE warning lamp should
glow and go OFF when the ignition switch returns to the
RUN position.
The following conditions will activate the BRAKE lamp:
S Parking brake applied. The light should be ON
whenever the parking brake is applied and the igni-
tion switch is ON.
S Low fluid level. A low fluid level in the master cylin-
der will turn the BRAKE lamp ON.
S EBD system is disabled. The light should be ON
when the EBD system is malfunctioning.

4E1 – 6IREAR DISC BRAKES
DAEWOO V–121 BL4
2. Apply a few drops of thread–locking compound to
the caliper bracket mounting bolts and install the
caliper bracket.
Tighten
Tighten the caliper bracket mounting bolts to 56 NSm
(41 lb–ft).
3. Install the brake shoes and the caliper. See ”Cali-
per” in this section.
HUB AND PARKING BRAKE
SHOE/BACKPLATE
Removal Procedure
1. Remove the caliper mounting bracket.
2. Remove the rotor detent screw.
3. Remove the rotor.
4. Remove the rear ABS sensor connector.

4F – 60IANTILOCK BRAKE SYSTEM
DAEWOO V–121 BL4
MAINTENANCE AND REPAIR
ON–VEHICLE SERVICE
SERVICE PRECAUTIONS
CAUTION : Brake fluid may irritate eyes and skin. In
case of contact, take the following actions:
S Eye contact – rinse thoroughly with water.
S Skin contact – wash with soap and water.
S Ingestion – consult a physician immediately.
CAUTION : To help avoid personal injury due to poor
braking, DO NOT tap into the vehicle’s brake system
to operate a trailer brake system.
Notice : When fasteners are removed, always reinstall
them at the same location from which they were removed.
If a fastener needs to be replaced, use the correct part
number fastener for that application. If the correct part
number fastener is not available, a fastener of equal size
and strength (or stronger) may be used. Fasteners that
are not reused, and those requiring thread–locking com-
pound will be called out. The correct torque values must
be used when installing fasteners that require them. If the
above procedures are not followed, parts or system dam-
age could result.
Notice : Use only DOT 3 equivalent hydraulic brake fluid.
The use of DOT 5 (silicone) brake fluid is not recom-
mended. Reduced brake performance or durability may
result.
Notice : Avoid spilling brake fluid on any of the vehicle’s
painted surfaces, wiring, cables, or electrical connectors.
Brake fluid will damage paint and electrical connections.
If any fluid is spilled on the vehicle, flush the area with wa-
ter to lessen the damage.
Computer System Service Precautions
Take care to avoid electronic brake control module
(EBCM) circuit overloading. In testing for opens or shorts,
do not ground or apply voltage to any circuit unless
instructed to do so by the diagnostic procedure. Test cir-
cuits only with a high–impedance multimeter. Never re-
move or apply power to any control module with the igni-
tion switch in the ON position. Always turn the ignition to
the OFF position before removing or connecting battery
cables, fuses, or connectors.
General Service Precautions
S Disconnect the EBCM connector before performing
any vehicle welding work using an electric arc weld-
er.
S Do not attempt to disassemble any component des-
ignated as nonserviceable. The hydraulic modulator
and the EBCM can be separated from each other
and replaced separately but cannot be serviced.
They have no replaceable parts, and there is no
access to the components they contain.

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.