ESP DAEWOO NUBIRA 2004 Service Owner's Guide

1F – 630IENGINE CONTROLS
DAEWOO V–121 BL4
COMPREHENSIVE COMPONENT
MONITOR DIAGNOSTIC OPERATION
Comprehensive component monitoring diagnostics are
required to monitor emissions–related input and output
powertrain components.
Input Components
Input components are monitored for circuit continuity and
out–of–range values. This includes rationality checking.
Rationality checking refers to indicating a fault when the
signal from a sensor does not seem reasonable, i.e.
Throttle Position (TP) sensor that indicates high throttle
position at low engine loads or Manifold Absolute Pressure
(MAP) voltage. Input components may include, but are not
limited to, the following sensors:
S Vehicle Speed Sensor (VSS).
S Crankshaft Position (CKP) sensor.
S Throttle Position (TP) sensor.
S Engine Coolant Temperature (ECT) sensor.
S Camshaft Position (CMP) sensor.
S Manifold Absolute Pressure (MAP) sensor.
In addition to the circuit continuity and rationality check,
the ECT sensor is monitored for its ability to achieve a
steady state temperature to enable closed loop fuel con-
trol.
Output Components
Output components are diagnosed for proper response to
control module commands. Components where functional
monitoring is not feasible will be monitored for circuit conti-
nuity and out–of–range values if applicable. Output com-
ponents to be monitored include, but are not limited to the
following circuit:
S Idle Air Control (IAC) Motor.
S Control module controlled EVAP Canister Purge
Valve.
S A/C relays.
S Cooling fan relay.
S VSS output.
S MIL control.
Refer to ”Engine Control Module” and Sensors in this sec-
tion.
Passive and Active Diagnostic Tests
A passive test is a diagnostic test which simply monitors
a vehicle system or component. Conversely, an active
test, actually takes some sort of action when performing
diagnostic functions, often in response to a failed passive
test. For example, the Exhaust Gas Recirculation (EGR)
diagnostic active test will force the EGR valve open during
closed throttle deceleration and/or force the EGR valve
closed during a steady state. Either action should result in
a change in manifold pressure.
Intrusive Diagnostic Tests
This is any on–board test run by the Diagnostic Manage-
ment System which may have an effect on vehicle perfor-
mance or emission levels.
Warm–Up Cycle
A warm–up cycle means that engine temperature must
reach aminimum of 160°F (70°C) and rise at least 72°F
(22°C) over the course of a trip.
Freeze Frame
Freeze Frame is an element of the Diagnostic Manage-
ment System which stores various vehicle information at
the moment an emissions–related fault is stored in
memory and when the Malfunction Indicator Lamp (MIL)
is commanded on. These data can help to identify the
cause of a fault.
Failure Records
Failure Records data is an enhancement of the EOBD
Freeze Frame feature. Failure Records store the same ve-
hicle information as does Freeze Frame, but it will store
that information for any fault which is stored in onboard
memory, while Freeze Frame stores information only for
emission–related faults that command the MIL on.
COMMON EOBD TERMS
Diagnostic
When used as a noun, the word diagnostic refers to any
on–board test run by the vehicle’s Diagnostic Manage-
ment System. A diagnostic is simply a test run on a system
or component to determine if the system or component is
operating according to specification. There are many diag-
nostics, shown in the following list:
S Misfire
S Front Heated Oxygen Sensor (HO2S1)
S Rear Heated Oxygen Sensor (HO2S2)
S Exhaust Gas Recirculation (EGR)
S Catalyst monitoring
Enable Criteria
The term ”enable criteria” is engineering language for the
conditions necessary for a given diagnostic test to run.
Each diagnostic has a specific list of conditions which
must be met before the diagnostic will run.
”Enable criteria” is another way of saying ”conditions re-
quired.”
The enable criteria for each diagnostic is listed on the first
page of the Diagnostic Trouble Code (DTC) description
under the heading ”Conditions for Setting the DTC.” En-
able criteria varies with each diagnostic and typically in-
cludes, but is not limited to, the following items:
S Engine speed.
S Vehicle speed
S Engine Coolant Temperature (ECT)
S Manifold Absolute Pressure (MAP)

ENGINE CONTROLS 1F – 633
DAEWOO V–121 BL4
Failed This Ig. (Failed This Ignition)
This message display indicates that the diagnostic test
has failed at least once during the current ignition cycle.
This message will clear when DTCs are cleared or the igni-
tion is cycled.
History
This message display indicates that the DTC has been
stored in memory as a valid fault. A DTC displayed as a
History fault may not mean that the fault is no longer pres-
ent. The history description means that all the conditions
necessary for reporting a fault have been met (maybe
even currently), and the information was stored in the con-
trol module memory.
MIL Requested
This message display indicates that the DTC is currently
causing the MIL to be turned ON. Remember that only
type A and type B DTCs can request the MIL. The MIL re-
quest cannot be used to determine if the DTC fault condi-
tions are currently being experienced. This is because the
diagnostic executive will require up to three trips during
which the diagnostic test passes to turn OFF the MIL.
Not Run Since CI (Not Run Since Cleared)
This message display indicates that the selected diagnos-
tic test has not run since the last time DTCs were cleared.
Therefore, the diagnostic test status (passing or failing) is
unknown. After DTCs are cleared, this message will con-
tinue to be displayed until the diagnostic test runs.
Not Run This Ig. (Not Run This Ignition)
This message display indicates that the selected diagnos-
tic test has not run during this ignition cycle.
Test Ran and Passed
This message display indicates that the selected diagnos-
tic test has done the following:
S Passed the last test.
S Run and passed during this ignition cycle.
S Run and passed since DTCs were last cleared.
If the indicated status of the vehicle is ”Test Ran and
Passed” after a repair verification, the vehicle is ready to
be released to the customer.
If the indicated status of the vehicle is ”Failed This Ignition”
after a repair verification, then the repair is incomplete and
further diagnosis is required.
Prior to repairing a vehicle, status information can be used
to evaluate the state of the diagnostic test, and to help
identify an intermittent problem. The technician can con-
clude that although the MIL is illuminated, the fault condi-
tion that caused the code to set is not present. An intermit-
tent condition must be the cause.
PRIMARY SYSTEM – BASED
DIAGNOSTICS
There are primary system–based diagnostics which eval-
uate system operation and its effect on vehicle emissions.
The primary system–based diagnostics are listed below
with a brief description of the diagnostic function:
Oxygen Sensor Diagnosis
The fuel control Front Heated Oxygen Sensor (HO2S1) is
diagnosed for the following conditions:
S Slow response.
S Response time (time to switch R/L or L/R).
S Inactive signal (output steady at bias voltage
approx. 450 mv).
S Signal fixed high.
S Signal fixed low.
The catalyst monitor Rear Heated Oxygen Sensor
(HO2S2) is diagnosed for the following conditions:
S Heater performance (time to activity on cold start).
S Signal fixed low during steady state conditions or
power enrichment (hard acceleration when a rich-
mixture should be indicated).
S Signal fixed high during steady state conditions or
deceleration mode (deceleration when a lean mix-
ture should be indicated).
S Inactive sensor (output steady at approximately 438
mv).
If the oxygen sensor pigtail wiring, connector or terminal
are damaged, the entire oxygen sensor assembly must be
replaced. Do not attempt to repair the wiring, connector or
terminals. In order for the sensor to function properly, it
must have clean reference air provided to it. This clean air
reference is obtained by way of the oxygen sensor wire(s).
Any attempt to repair the wires, connector or terminals
could result in the obstruction of the reference air and de-
grade oxygen sensor performance.
Misfire Monitor Diagnostic Operation
The misfire monitor diagnostic is based on crankshaft
rotational velocity (reference period) variations. The en-
gine control module (ECM) determines crankshaft rota-
tional velocity using the Crankshaft Position (CKP) sensor
and the Camshaft Position (CMP) sensor. When a cylinder
misfires, the crankshaft slows down momentarily. By mon-
itoring the CKP and CMP sensor signals, the ECM can cal-
culate when a misfire occurs.
For a non–catalyst damaging misfire, the diagnostic will be
required to monitor a misfire present for between
1000–3200 engine revolutions.
For catalyst–damaging misfire, the diagnostic will respond
to misfire within 200 engine revolutions.
Rough roads may cause false misfire detection. A rough
road will cause torque to be applied to the drive wheels and
drive train. This torque can intermittently decrease the
crankshaft rotational velocity. This may be falsely de-
tected as a misfire.

2B – 10IWHEEL ALIGNMENT
DAEWOO V–121 BL4
GENERAL DESCRIPTION
AND SYSTEM OPERATION
FOUR WHEEL ALIGNMENT
The first responsibility of engineering is to design safe
steering and suspension systems. Each component must
be strong enough to withstand and absorb extreme pun-
ishment. Both the steering system and the front and the
rear suspension must function geometrically with the body
mass.
The steering and the suspension systems require that the
front wheels self–return and that the tire rolling effort and
the road friction be held to a negligible force in order to al-
low the customer to direct the vehicle with the least effort
and the most comfort.
A complete wheel alignment check should include mea-
surements of the rear toe and camber.
Four–wheel alignment assures that all four wheels will be
running in precisely the same direction.
When the vehicle is geometrically aligned, fuel economy
and tire life are at their peak, and steering and perfor-
mance are maximized.
TOE
Toe–in is the turning in of the tires, while toe–out is the
turning out of the tires from the geometric centerline or
thrust line. The toe ensures parallel rolling of the wheels.
The toe serves to offset the small deflections of the wheel
support system which occur when the vehicle is rolling for-
ward. The specified toe angle is the setting which achieves
0 degrees of toe when the vehicle is moving.
Incorrect toe–in or toe–out will cause tire wear and re-
duced fuel economy. As the individual steering and sus-
pension components wear from vehicle mileage, addition-
al toe will be needed to compensate for the wear.
Always correct the toe dimension last.
CASTER
Caster is the tilting of the uppermost point of the steering
axis either forward or backward from the vertical when
viewed from the side of the vehicle. A backward tilt is posi-
tive, and a forward tilt is negative. Caster influences direc-
tional control of the steering but does not affect tire wear.
Weak springs or overloading a vehicle will affect caster.
One wheel with more positive caster will pull toward the
center of the car. This condition will cause the car to move
or lean toward the side with the least amount of positive
caster. Caster is measured in degrees and is not adjust-
able.
CAMBER
Camber is the tilting of the top of the tire from the vertical
when viewed from the front of the vehicle. When the tires
tilt outward, the camber is positive. When the tires tilt in-
ward, the camber is negative. The camber angle is mea-
sured in degrees from the vertical. Camber influences
both directional control and tire wear.
If the vehicle has too much positive camber, the outside
shoulder of the tire will wear. If the vehicle has too much
negative camber, the inside shoulder of the tire will wear.
Camber is not adjustable.
STEERING AXIS INCLINATION
Steering Axis Inclination (SAI) is the tilt at the top of the
steering knuckle from the vertical. Measure the SAI angle
from the true vertical to a line through the center of the strut
and the lower ball joint as viewed from the front of the ve-
hicle.
SAI helps the vehicle track straight down the road and as-
sists the wheel back into the straight ahead position. SAI
on front wheel drive vehicles should be negative.
INCLUDED ANGLE
The included angle is the angle measured from the cam-
ber angle to the line through the center of the strut and the
lower ball joint as viewed from the front of the vehicle.
The included angle is calculated in degrees. Most align-
ment racks will not measure the included angle directly. To
determine the included angle, subtract the negative or add
the positive camber readings to the Steering Axis Inclina-
tion (SAI).
SCRUB RADIUS
The scrub radius is the distance between true vertical and
the line through the center of the strut and lower ball joint
to the road surface. Scrub radius is built into the design of
the vehicle. Scrub radius is not adjustable.
SETBACK
The setback is the distance in which one front hub and
bearing assembly may be rearward of the other front hub
and bearing assembly. Setback is primarily caused by a
road hazard or vehicle collision.
TURNING ANGLE
The turning angle is the angle of each front wheel to the
vertical when the vehicle is making a turn.

TIRES AND WHEELS 2E – 7
DAEWOO V–121 BL4
Recoating Procedure
CAUTION : To avoid serious personal injury when ap-
plying any two–part component paint system, follow
the specific precautions provided by the paint
manufacturer. Failure to follow these precautions
may cause lung irritation and an allergic respiratory
reaction.
1. Clean the surface.
2. Soak the wheel with Amchem Alumi Prep No. 33 or
equivalent for 1 to 3 minutes. Rinse the wheel with
water and blow it dry.
3. Soak the wheel with Amchem Alodine No. 1001 or
equivalent for 1 to 3 minutes. Rinse the wheel with
water and blow it dry.
4. Finish with Ditzler Delclear Urethane and Ditzler
Ultra–Urethane Additive or equivalent, using three
coats.
1st coat – spray on a light mist coat; let dry.
2nd coat – spray or paint on a light coat; let dry.
3rd coat – spray or paint on a heavy double wet
coat; let dry.
5. Let the urethane dry for 24 hours or flash for 30
minutes and force dry at 60°C (140°F) for 30 min-
utes. Allow the urethane to cool for 5 minutes be-
fore mounting the wheel on the vehicle.
OFF–VEHICLE BALANCING
Perform wheel balancing with an electronic off–vehicle ba-
lancer. The balancer is easy to use and gives both a static
and a dynamic balance. Unlike on–vehicle balancing, the
off–vehicle balancer does not correct for drum or rotor im-
balance. This drawback is overcome by its accuracy (usu-
ally to within 1/8 ounce). Secure the wheel on the balancer
with a cone through the back side of the centerhole, not
through the wheel bolt holes.
CORRECTING NON–UNIFORM TIRES
There are two ways to correct properly balanced tires
which still vibrate. One method uses an automatic ma-
chine which loads the tire and buffs small amounts of rub-
ber from high spots on the outer two tread rows. Correction
by this method is usually permanent and, if it is done prop-
erly, does not significantly affect the appearance or the
tread life of the tire. Tire truing with a blade–type machine
is not recommended because it substantially reduces the
tread life and often does not correct the problem perma-
nently.
Another method is to dismount the tire and rotate it 180 de-
grees on the rim. Do this only on the tire and wheel assem-
blies which are known to be causing a vibration because
this method is just as likely to cause good assemblies to
vibrate.

2E – 10ITIRES AND WHEELS
DAEWOO V–121 BL4
turers of tire chains have a specific chain size for each tire
size to ensure a proper fit when the chain is installed. Be
sure to purchase the correct chains for the tires on which
they are to be used. Use rubber adjusters to take up any
slack or clearance in loose chains.
Use of chains may adversely affect vehicle handling.
When tire chains are installed, follow these precautions:
S Adjust speed to road conditions.
S Avoid sharp turns.
S Avoid locked–wheel braking.
To prevent chain damage to the vehicle, install the chains
on the front tires as tightly as possible. Tighten them again
after driving 0.4 to 0.8 kilometer (0.3 to 0.5 mile). The use
of chains on the rear tires is not recommended because
they may contact the vehicle and possibly damage it. If
chains must be used on the rear tires, be sure there is suffi-
cient clearance between the chains and the body. Do not
exceed 70 km/h (45 mph) or the chain manufacturer’s
speed limit, if lower. Avoid large bumps, potholes, severe
turns and any other maneuvers which could cause the
tires to bounce. Follow any other instructions of the chain
manufacturer which do not disagree with the above in-
structions.
REPLACEMENT TIRES
A tire performance criteria (TPC) specification number is
molded in the sidewall near the tire size of all original
equipment tires. This specification number assures that
the tire meets performance standards for traction, endur-
ance, dimensions, noise, handling and rolling resis–tance.
Usually a specific TPC number is assigned to each tire
size.
CAUTION : Do not mix different types of tires on the
same vehicle such as radial, bias and bias–belted
tires except in emergencies, because vehicle han-
dling may be seriously affected and may result in loss
of control.
Use only replacement tires with the same size, load range,
and construction as the original. The use of any other tire
size or construction type may seriously affect ride, han-
dling, speedometer/odometer calibration, vehicle ground
clearance, and tire clearance to the body and the chassis.
This does not apply to the spare tire furnished with the ve-
hicle.
It is recommended that new tires be installed in pairs on
the same axle.
If it is necessary to replace only one tire, pair it with the tire
having the most tread to equalize the braking action.
Although they may appear different in tread design, tires
built by different manufacturers with identical TPC specifi-
cations may be used on the same vehicle.
ALL SEASON TIRES
Most vehicles are now equipped with steel–belted all sea-
son radial tires as standard equipment. These tires qualify
as snow tires, with a 37 percent higher average rating for
snow traction than the non–all season radial tires pre-
viously used. Other performance areas, such as wet trac-
tion, rolling resistance, tread life, and air retention, have
also been improved. This was done by improvements in
both tread design and tread compounds. These tires are
identified by an ”M + S” molded in the tire sidewall following
the size number. The suffix ”MS” is also molded in the side-
wall after the TPC specification number.
The optional handling tires used on some vehicles are not
all season tires. These will not have the ”MS” marking after
the tire size or the TPC specification number.
PASSENGER METRIC SIZED TIRES
All Daewoo vehicles now use Passenger (P) metric sized
tires. P–metric tires are available in two load ranges: stan-
dard load (35 psi maximum) and extra load (41 psi maxi-
mum). Most passenger vehicle tires are standard load.
Most P–metric tire sizes do not have exact corresponding
alphanumeric tire sizes. For example, a P175/70R13 is
not exactly equal in size and load–carrying capacity to an
FR70–13. For this reason, replacement tires should be of
the same TPC specification number as the originals. If P–
metric tires must be replaced with other sizes, consult a
tire dealer. Tire companies can best recommend the clos-
est match of alphanumeric to P–metric sizes within their
own tire lines.
The metric term for measuring tire inflation pressure is the
kilopascal (kPa). Tire pressure may be printed in both kPa
and psi. One psi equals 6.895 kPa.
See the tire label or refer to ”Tire Size and Pressure Speci-
fications” in this section for tire inflation pressures.
TIRE LABEL
The tire label is permanently located on the rear face of the
driver’s door and should be referred to for tire information.
It lists the maximum vehicle load, the tire size (including
the spare tire), and the cold inflation pressure (including
the spare tire).
SPARE TIRE
The notchback and the wagon come equipped with a full–
sized tire on a steel wheel. The hatchback comes
equipped with a reduced–sized temporary tire on a steel
wheel.
WHEELS
Wheels must be replaced if they are bent, dented, have
excessive lateral or radial runout, leak air through welds,
have elongated bolt holes, or if the wheel bolts won’t stay
tight or are heavily rusted. Wheels with excessive runout
may cause vehicle vibration. Replacement wheels must
be equivalent to the original equipment wheels in load ca-

4F – 22IANTILOCK BRAKE SYSTEM
DAEWOO V–121 BL4
SELF–DIAGNOSTICS
Important : The electronic brake control module (EBCM)
turns the valve relay off when a diagnostic trouble code
(DTC) is set. The scan tool will indicate that the valve relay
is off when it is used to monitor the data list. This is normal
and should not be considered a malfunction.
Important : For safety reasons it is recommended that the
vehicle not be driven with test equipment connected. Ex-
ception : for testing of wheel speeds provided the test reg-
ulations are met.
The EBCM performs system self–diagnostics and can de-
tect and often isolate system malfunctions. When it de-
tects a malfunction, the EBCM sets a DTC that represents
the malfunction, turns ON the ABS and/or the EBD indica-
tors in most instances, and may disable the ABS and/or
the EBD functions as necessary for the duration of the igni-
tion cycle.
Once each ignition cycle, the EBCM performs an automat-
ic test when the vehicle speed > 6 km/h and the brake ped-
al is not actuated or when the vehicle speed > 15 km/h and
the brake pedal is actuated. In the course of this test, the
system cycles each valve solenoid and the pump motor,
along with the necessary relays, to check component op-
eration. If the EBCM detects any malfunctions, it will set
a DTC as described above.
DISPLAYING DTCS
Tools Required
Scan Tool
DTCs can be read through the use of the scan tool.
CLEARING DTCS
Tools Required
Scan Tool
The diagnostic trouble codes (DTCs) in the electronic
brake control module (EBCM) memory are erased:S Use the scan tool ”Clear DTCs” selection.
The method is detailed below. Be sure to verify proper sys-
tem operation and absence of DTCs when the clearing
procedure is completed.
The EBCM will not permit DTC clearing until all DTCs have
been displayed. Also, DTCs cannot be cleared by discon-
necting the EBCM, disconnecting the battery cables, or
turning the ignition switch to LOCK.
Scan Tool Method
The scan tool can clear ABS system DTCs using the mass
storage cartridge.
1. Install the scan tool and the mass storage cartridge.
2. Select ”Fault Memory.”
3. Select ”Clear Fault Memory.”
Clearing the fault memory cannot reset a valve relay which
was shut down when the fault was recognized. Changes
are possible only after the fault has been eliminated and
the next ignition cycle has begun.
INTERMITTENTS AND POOR
CONNECTIONS
As with most electronic systems, intermittent malfunctions
may be difficult to diagnose accurately. The following is a
method to try to isolate an intermittent malfunction, espe-
cially in wheel speed circuitry.
If an ABS malfunction occurs, the ABS indicator will illumi-
nate during the ignition cycle in which the malfunction was
detected. If it is an intermittent problem which seems to
have corrected itself (ABS indicator off), a history DTC will
be stored. Also stored will be the history data of the DTC
at the time the malfunction occurred. Use the scan tool
modular diagnostic system to read ABS history data.
Most intermittents are caused by faulty electrical connec-
tions or wiring, although a sticking relay or solenoid can oc-
casionally be at fault.

4F – 46IANTILOCK BRAKE SYSTEM
DAEWOO V–121 BL4
DTC C0121 – Valve Relay Circuit Malfunction
StepActionValue(s)YesNo
11. Use a scan tool to clear all DTCs.
2. Road test the vehicle.
Does DTC C0121 set again?–Go to Step 3Go to Step 2
21. Check all system wiring harness connectors
and terminals, especially the EBCM, for any
problem that could cause an intermittent condi-
tion.
2. Repair any intermittent problem found.
Is the repair complete?–System OK–
31. Disconnect ABS harness connector J1 from
the EBCM.
2. Examine terminal 19 on the harness connector
and the EBCM connector.
Is there damage or corrosion at terminal 19?–Go to Step 4Go to Step 5
4Repair the terminal or the connector, or replace the
ABS harness or ABS unit as required.
Is the resistance equal to the specified value?–System OK–
5Measure the resistance from terminal 19 of the har-
ness connector J1 to a good chassis ground.
Is the resistance equal to the specified value?
0 WGo to Step 6Go to Step 7
6Replace the ABS unit.
Is the repair complete?–System OK–
7Measure the resistance from terminal 19 of the har-
ness connector J1 to the ground lug at G106.
Is the resistance equal to the specified value?
0 WGo to Step 8Go to Step 9
8Repair the chassis connection at the ground lug.
Is the repair complete?–System OK–
9Repair the open or the high resistance in the ABS
harness, or replace the harness as required.
Is the repair complete?–System OK–

ANTILOCK BRAKE SYSTEM 4F – 55
DAEWOO V–121 BL4
DTC C0550 – ABS Control Module Internal Fault
StepActionValue(s)YesNo
1Use the scan tool to determine if any other DTCs are
set.
Are other DTCs set?–Go to the
tables for the
other DTCsGo to Step 2
2Clear all DTCs and road test the vehicle.
Does DTC C0550 set again?–Go to Step 4Go to Step 3
31. Check all wiring harness connectors and termi-
nals, especially those at the EBCM, for any
condition that could cause an intermittent.
2. Repair any problems found.
Is the repair complete?–System OK–
41. Turn the ignition switch to OFF.
2. Disconnect EBCM connector J1.
3. Turn the ignition switch to ON.
4. Measure the voltage between ground and ter-
minals 15, 17, and 18 of the EBCM harness
connector J1.
Is the voltage equal to the specified value?11–14 vGo to Step 6Go to Step 5
51. Check the voltage supply and the ground con-
nections to the EBCM.
2. Repair any open or high resistance found.
Is the repair complete?–System OK–
6Check the EBCM connector J1 for any ineffective
terminals.
Are there any problems?–Go to Step 7Go to Step 8
7Repair any connector problem found.
Is the repair complete?–System OK–
8Clear all DTCs and road test the vehicle.
Does DTC C0550 set again?–Go to Step 9System OK
9Replace the ABS unit.
Is the repair complete?–System OK–

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.

ZF 4 HP 16 AUTOMATIC TRANSAXLE 5A1 – 43
DAEWOO V–121 BL4
DIAGNOSTIC INFORMATION AND
PROCEDURES DIAGNOSIS
BASIC KNOWLEDGE REQUIRED
You must be familiar with some basic electronics to use
this section of the Service Manual. They will help you to
follow diagnostic procedures.
Notice : Lack of the basic knowledge of this transaxle
when performing diagnostic procedures could result in in-
correct diagnostic performance or damage to transaxle
components.
Do not, under any circumstances, attempt to diagnose a
transaxle problem without this basic knowledge.
Notice : If a wire is probed with a sharp instrument and not
properly sealed afterward, the wire will corrode and an
open circuit will result.
Diagnostic test probes are now available that allow you to
probe individual wires without leaving the wire open to the
environment. These probe devices are inexpensive and
easy to install, and they permanently seal the wire from
corrosion.
Special Tools
You should be able to use a Digital Volt Meter (DVM), a cir-
cuit tester, jumper wires or leads and a line pressure gauge
set.
The functional check procedure is designed to verify the
correct operation of electronic components in the trans-
axle.
This will eliminate the unnecessary removal of transaxle
components.
FUNCTIONAL CHECK PROCEDURE
Begin with the Functional Check Procedure which pro-
vides a general outline of how to diagnose automatic
transaxle. The following functional check procedure will in-
dicate the proper path of diagnosing the transaxle by de-
scribing the basic checks and then referencing the loca-
tions of the specific checks.
S Check the fluid level according to the Fluid Level
Service Procedure.
S Check the transaxle for fluid leaks.
S Check if the transaxle fluid is not burnt by color and
smell.
S Ensure that the transaxle is not in Limp Home
Mode(LHM).
S Check the battery terminals and the ground con-
nections for corrosion or looseness.
S Check that the cooler flow is not restricted.S Check all electrical connections for tightness.
S Use on–board diagnostic tool or a scan tool to see
if any transaxle trouble codes have been set. Refer
to the appropriate ”Diagnostic Trouble Code (DTC)”
information and repair the vehicle as directed. After
repairing the vehicle, perform the road test and
verify that the code has not set again.
S Perform the Electrical/Garage Shift Tests.
S Perform the Road Test Procedure in this section.
S Inspect the oil and check for metal or other contam-
inants in the oil pan.
LINE PRESSURE CHECK
PROCEDURE
The 4HP 16 A/T uses a trochoid type oil pump to produce
hydraulic pressure, and a pressure control solenoid (sole-
noid 1) to control that pressure at the pressure regulator
valve, after it leaves the pump. The transaxle pressure
control solenoid is controlled by an electrical signal that
ranges from 0 to 12 volts corresponds to minimum line
pressure (approx. 89.9 to 124.7 psi (6.2 to 8.6 bar)) and
0 volt corresponds to a maximum line pressure (approx.
221.9 to 252.4 psi (15.3 to 17.4 bar)) in all range.
Line pressures are calculated for two sets of gear ranges
– Drive–Park–Neutral and Reverse. This allow the trans-
axle line pressure to be appropriate for different pressure
needs in different gear ranges:
Gear
Range
Solenoid
1RPMPressure
Drive,
ReverseOff2,500221.9~252.4psi
(15.3~17.4 bar)
On2,50017.4~269.8psi
(1.2~18.6 bar)
Neutral,
ParkOff2,500221.9~252.4psi
(15.3~17.4 bar)
On2,50089.9~269.8 psi
(6.2~18.6 bar)
Before performing a line pressure check, verify that the
pressure control solenoid is receiving the correct electrical
signal from the TCM:
1. Install a scan tool.
2. Start the engine and set parking brake.
3. Check for a stored pressure control solenoid diag-
nostic trouble code, and other diagnostic trouble
codes.