tow DAEWOO LACETTI 2004 Service Repair Manual

GENERAL INFORMATION 0B – 11
DAEWOO V–121 BL4
Chassis and Body
Maintenance ItemMaintenance Interval
Kilometers or time in months, whichever comes first
x 1,000 km1153045607590105120
x 1,000 miles0.6918273645546372
Months–1224364860728496
Interior air filter (A/C)RRRRRRRR
Exhaust pipes & mountingsIIIIIIII
Brake/Clutch fluid (1) (4)IIRIRIRIR
Front brake pads and discs(3)IIIIIIII
Rear brake pads & discs or drums and
linings (3)IIIIIIII
Parking brakeIIIIIIIII
Brake line and connections (Including
booster)IIIIIIII
Manual Transaxle Oil *(1)IIIIIIII
Automatic transaxle fluid *(1) (5)IIIIIIII
Tighten chassis and underbody bolts
and nutsIIIIIIII
Tire condition and inflation pressureIIIIIIIII
Wheel alignment (2)Inspect when abnormal condition is noted
Steering wheel and linkageIIIIIIII
Power steering fluid & lines* (1)IIIIIIIII
Drive shaft bootsIIIIIIII
Seat belts, buckles and anchorsIIIIIIII
Lubricate locks, hinges and hood
latchIIIIIIII
Chart Symbols:
I – Inspect and if necessary correct, clean, replenish, or adjust.
R – Replace or change:
(1) Refer to Recommended Fluids And Lubricants.
(2) And if necessary, rotate and balance wheels.
(3) More frequent if operated under severe conditions: short distance driving, extensive idling, frequent low–speed oper-
aion in stop and go traffic, or driving in dusty conditions.
(4) Change the brake/clutch fluid every 15,000 km (9,000 miles), if the vehicle is mainly driven under the following severe
conditions: driving in hilly or mountainous terrain, or towing a trailer/caravan frequently.
(5) 1.8 DOHC model (ZF 4HP16 Automatic Transaxle): Change automatic transaxle fluid every 60,000 Km (36,000 miles)
if the vehicle is mainly driven under any of the following severe conditions:
S In heavy city traffic where the outside temperature regularly reaches 32°C (90°F) or higher, or
S In hilly or mountainous terrain, or
S When doing frequent trailer towing, or
S Uses such as taxi, police or delivery service.

0B – 12IGENERAL INFORMATION
DAEWOO V–121 BL4
OWNER INSPECTIONS AND SERVICES
WHLE OPERATING THE VEHICLE
Horn Operation
Blow the horn occasionally tomake sure it works. Check
all the button locations.
Brake System Operation
Be alert for abnormal sounds, increased brake pedal trav-
el or repeated pulling to one side when braking. Also, if the
brake warning light goes on, or flashes, something may be
wrong with part of the brake system.
Exhaust System Operation
Be alert to any changes in the sound of the system or the
smell of the fumes. These are signs that the system may
be leaking or overheating. Have the system inspected and
repaired immediately.
Tires,Wheels and Alignment Operation
Be alert to any vibration of the steering wheel or the seats
at normal highway speeds. This may mean a wheel needs
to be balanced. Also, a pull right or left on a straight, level
road may show the need for a tire pressure adjustment or
a wheel alignment.
Steering System Operation
Be alert to changes in the steering action. An inspection
is needed when the steering wheel is hard to turn or has
too much free play, or if unusual sounds are noticed when
turning or parking.
Headlight Aim
Take note of the light pattern occasionally. Adjust the
headlights if the beams seem improperly aimed.
AT EACH FUEL FILL
A fluid loss in any (except windshield washer) system may
indicate a problem. Have the system inspected and re-
paired immediately.
Engine Oil Level
Check the oil level and add oil if necessary. The best time
to check the engine oil level is when the oil is warm.
1. After stopping the engine, wait a few minutes for
the oil to drain back to the oil pan.
2. Pull out the oil level indicator (dip stick).
3. Wipe it clean, and push the oil level indicator back
down all the way.
4. Pull out the oil level indicator and look at the oil lev-
el on it.
5. Add oil, if needed, to keep the oil level above the
MIN line and within the area labeled ”Operating
Range.” Avoid overfilling the engine, since this may
cause engine damage.
6. Push the indicator all the way back down into the
engine after taking the reading.If you check the oil level when the oil is cold, do not run the
engine first. The cold oil will not drain back to the pan fast
enough to give a true oil level reading.
Engine Coolant Level and Condition
Check the coolant level in the coolant reservoir tank and
add coolant if necessary. Inspect the coolant. Replace
dirty or rusty coolant.
Windshield Washer Fluid Level
Check the washer fluid level in the reservoir. Add fluid if
necessary.
AT LEAST MONTHLY
Tire And Wheel Inspection and Pressure
Check
Check the tires for abnormal wear or damage. Also check
for damaged wheels. Check the tire pressure when the
tires are cold (check the spare also, unless it is a stow-
away). Maintain the recommended pressures that are on
the tire placard that is in the glove box.
Light Operation
Check the operation of the license plate light, the head-
lights (including the high beams), the parking lights, the
fog lights, the taillight, the brake lights, the turn signals, the
backup lights and the hazard warning flasher.
Fluid Leak Check
Periodically inspect the surface beneath the vehicle for
water, oil, fuel or other fluids, after the vehicle has been
parked for a while. Water dripping from the air conditioning
system after use is normal. If you notice fuel leaks or
fumes, find the cause and correct it at once.
AT LEAST TWICE A YEAR
Power Steering System Reservoir Level
Check the power steering fluid level. Keep the power
steering fluid at the proper level. Refer to Section 6A, Pow-
er Steering System.
Brake Master Cylinder Reservoir Level
Check the fluid and keep it at the proper level. A low fluid
level can indicate worn disc brake pads which may need
to be serviced. Check the breather hole in the reservoir
cover to be free from dirt and check for an open passage.
Clutch Pedal Free Travel
Check clutch pedal free travel and adjust as necessary.
Measure the distance from the center of the clutch pedal
to the outer edge of the steering wheel with the clutch ped-
al not depressed. Then measure the distance from the
center of the clutch pedal to the outer edge of the steering
wheel with the clutch pedal fully depressed. The difference
between the two values must be greater than 130 mm
(5.19 inches).
Weather–Strip Lubrication
Apply a thin film silicone grease using a clean cloth.

GENERAL INFORMATION 0B – 13
DAEWOO V–121 BL4
EACH TIME THE OIL IS CHANGED
Automatic Transaxle Fluid
Refer to fluid level service procedure of Section 5A, ZF
4HP16 Automatic Transaxle.
Manual Transaxle
Check the fluid level and add fluid as required. Refer to
Section 5B, Five–Speed Manual Transaxle.
Brake System Inspection
This inspection should be done when the wheels are re-
moved for rotation. Inspect the lines and the hoses for
proper hookup, binding, leaks, cracks, chafing, etc. In-
spect the disc brake pads for wear. Inspect the rotors for
surface condition. Also inspect the drum brake linings for
wear and cracks. Inspect other brake parts, including the
drums, the wheels cylinders, the parking brake, etc., at the
same time. Check the parking brake adjustment. Inspect
the brakes more often if habit or conditions result in fre-
quent braking.
Steering, Suspension and Front Drive Axle
Boot And Seal Inspection
Inspect the front and rear suspension and the steering
system for damaged, loose or missing parts, signs of wear
or lack of lubrication. Inspect the power steering lines and
the hoses for proper hookup, binding, leaks, cracks, chaf-
ing, etc. Clean and inspect the drive axle boot and seals
for damage, tears or leakage. Replace the seals if neces-
sary.
Exhaust System Inspection
Inspect the complete system (including the catalytic con-
verter if equipped). Inspect the body near the exhaust sys-
tem. Look for broken, damaged, missing, or out–of–posi-
tion parts as well as open seams, holes, loose
connections, or other conditions which could cause heat
buildup in the floor pan or could let exhaust fumes seep
into the trunk or passenger compartment.
Throttle Linkage Inspection
Inspect the throttle linkage for interference or binding,
damaged, or missing parts. Lubricate all linkage joints and
throttle cable joints, the intermediate throttle shaft bearing,
the return spring at throttle valve assembly, and the accel-
erator pedal sliding face with suitable grease. Check the
throttle cable for free movements.
Engine Drive Belts
Inspect all belts for cracks, fraying, wear and proper ten-
sion. Adjust or replace the belts as needed.
Hood Latch Operation
When opening the hood, note the operation of the secon-
dary latch. It should keep the hood from opening all the
way when the primary latch is released. The hood must
close firmly.
AT LEAST ANNUALLY
Lap and Shoulder Belts Condition and
Operation
Inspect the belt system including: the webbing, the
buckles, the latch plates, the retractor, the guide loops and
the anchors.
Movable Head Restraint Operation
On vehicles with movable head restraints, the restraints
must stay in the desired position.
Spare Tire and Jack Storage
Be alert to rattles in the rear of the vehicle. The spare tire,
all the jacking equipment, and the tools must be securely
stowed at all times. Oil the jack ratchet or the screw mech-
anism after each use.
Key Lock Service
Lubricate the key lock cylinder.
Body Lubrication Service
Lubricate all the body door hinges including the hood, the
fuel door, the rear compartment hinges and the latches,
the glove box and the console doors, and any folding seat
hardware.
Transaxle Neutral Switch Operation on
Automatic Transaxle
CAUTION : Take the following precautions because
the vehicle could move without warning and possibly
cause personal injury or property damage:
S Firmly apply the parking brake and the regular
brakes.
S Do not use the accelerator pedal.
S Be ready to promptly turn off the ignition if the ve-
hicle starts.
On automatic transaxle vehicles, try to start the engine in
each gear. The starter should crank only in P (Park) or N
(Neutral).
Parking Brake and Transaxle P (Park)
Mechanism Operation
CAUTION : In order to reduce the risk of personal in-
jury or property damage, be prepared to apply the reg-
ular brakes promptly if the vehicle begins to move.
Park on a fairly steep hill with enough room for movement
in the downhill direction. To check the parking brake, with
the engine running and the transaxle in N (Neutral), slowly
remove foot pressure from the regular brake pedal (until
only the parking brake is holding the vehicle).
To check the automatic transaxle P (Park) mechanism’s
holding ability, release all brakes after shifting the trans-
axle to P (Park).
Underbody Flushing
Flushing the underbody will remove any corrosive materi-
als used for ice and snow removal and dust control. At
least every spring clean the underbody. First, loosen the
sediment packed in closed areas of the vehicle. Then flush
the underbody with plain water.

GENERAL ENGINE INFORMATION 1A – 3
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
20Inspect the bearing clearances.
Are the bearing clearances more than the specified
values?Crankshaft
0.026 ~0.046
mm
(0.0010~0.001
8 in.)
Connecting
Rod 0.019 ~
0.070 mm
(0.0007 ~
0.0027 in.)Go to Step 21Go to Step 22
21Replace the bearing, if necessary.
Is the repair complete?–Go to Step 1–
22Inspect the oil galleries.
Are the oil galleries cracked, porous, or plugged?–Go to Step 23Go to Step 24
23Repair or replace the engine block.
Is the repair complete?–Go to Step 1–
24Inspect the gallery plugs.
Are any of the gallery plugs missing or installed im-
properly?–Go to Step 25Go to Step 26
25Install the plugs or repair, as necessary.
Is the repair complete?–Go to Step 1–
26Inspect the camshaft.
Is the camshaft worn or is there evidence of poor
machining?–Go to Step 27System OK
27Replace the camshaft.
Is the repair complete?–Go to Step 1–
OIL LEAK DIAGNOSIS
Most fluid oil leaks are easily located and repaired by visu-
ally finding the leak and replacing or repairing the neces-
sary parts. On some occasions, a fluid leak may be difficult
to locate or repair. The following procedures may help you
in locating and repairing most leaks.
Finding the Leak:
1. Identify the fluid. Determine whether it is engine oil,
automatic transmission fluid, power steering fluid,
etc.
2. Identify where the fluid is leaking from.
1) After running the vehicle at normal operating
temperature, park the vehicle over a large sheet
of paper.
2) Wait a few minutes.
3) Find the approximate location of the leak by the
drippings on the paper.
3. Visually check around the suspected component.
Check around all the gasket mating surfaces for
leaks. A mirror is useful for finding leaks in areas
that are hard to reach.
4. If the leak still cannot be found, it may be neces-
sary to clean the suspected area with a degreaser,
steam, or spray solvent.
1) Thoroughly clean the area.2) Dry the area.
3) Operate the vehicle for several miles at normal
operating temperature and varying speeds.
4) After operating the vehicle, visually check the
suspected component.
5) If you still cannot locate the leak, try using the
powder or black light and dye method.
Powder Method:
1. Clean the suspected area.
2. Apply an aerosol–type powder, (such as foot pow-
der), to the suspected area.
3. Operate the vehicle under normal operating condi-
tions.
4. Visually inspect the suspected component. Trace
the leak path over the white powder surface to the
source.
Black Light and Dye Method:
A dye and light kit is available for finding leaks. Refer to the
manufacturer ’s directions when using the kit.
1. Pour the specified amount of dye into the engine oil
fill tube.
2. Operate the vehicle under normal operating condi-
tions as directed in the kit.
3. Direct the light toward the suspected area. The
dyed fluid will appear as a yellow path leading to
the source.

GENERAL ENGINE INFORMATION 1A – 7
DAEWOO V–121 BL4
Knocks at Idle Hot
StepActionValue(s)YesNo
1Does the engine knock at idle when hot?–Go to Step 2System OK
2Inspect the drive belts.
Are the belts loose or worn?–Go to Step 3Go to Step 4
3Tension or replace the belts, as necessary.
Is the repair complete?–Go to Step 1–
4Inspect the A/C compressor and the generator.
Is either the compressor or the generator faulty?–Go to Step 5Go to Step 6
5Replace the faulty A/C compressor or the generator.
Is the repair complete?–Go to Step 1–
6Inspect the valve train.
Are valve train components faulty?–Go to Step 7Go to Step 8
7Replace the faulty valve train components.
Is the repair complete?–Go to Step 1–
8Check the engine oil.
Is the proper viscosity oil used in the crankcase?–Go to Step 10Go to Step 9
9Install oil of the proper viscosity for the expected
seasonal temperatures.
Is the repair complete?–Go to Step 1–
10Inspect the piston pin clearance.
Is the clearance more than the specified value?0.020 mm
(0.0008 in.)Go to Step 11Go to Step 12
11Replace the piston and the pin.
Is the repair complete?–Go to Step 1–
12Check the connecting rod alignment.
Is the alignment faulty?–Go to Step 13Go to Step 14
13Check and replace rods, as necessary.
Is the repair complete?–Go to Step 1–
14Inspect the piston–to–bore clearance.
Is the clearance within the specified value?0.030 mm
(0.0012 in.)Go to Step 16Go to Step 15
15Hone the bore and fit a new piston.
Is the repair complete?Go to Step 1–
16Inspect the crankshaft balancer.
Is the balancer loose?–Go to Step 17Go to Step 18
17Torque or replace worn parts.
Is the repair complete?–Go to Step 1–
18Check the piston pin offset.
Is the offset at the specified value?0.5 ± 0.1 mm
(0.020 ~ 0.003
in.)
Toward Thrust
SideGo to Step 19System OK
19Install the correct piston.
Is the repair complete?–Go to Step 1–

1C2 – 2I1.8L DOHC ENGINE MECHANICAL
DAEWOO V–121 BL4
SPECIFICATIONS
ENGINE SPECIFICATIONS
ApplicationDescription
General Data:
Engine Type1.8L DOHCT18SED
Displacement1.8L DOHC1,799 cm3 (109.7 in3)
Bore Stroke1.8L DOHC81.6 x 86 mm (3.21 in. x 3.38 in.)
Compression Ratio9.6 ± 0.02:1
Firing Oder1–3–4–2
Cylinder Bore:
Diameter1.8L DOHC81.575~81.625 mm (3.2116~3.2135 in.)
Out of Round (Maximum)0.013 mm (0.0005 in.)
Taper (Maximum)0.013 mm (0.0005 in.)
Pistion:
Diameter1.8L DOHC81.575~82.105 mm (3.2115~3.2325 in.)
Clearance to Bore0.0100~0.0300 mm (0.00039~0.00110 in.)
Piston Protrusion0.5 mm (0.019 in.) Maximum
Piston Taper0.013 (0.0005 in.)
Piston Rings:
Ring, End Gap: Top Compression0.3~0.5 mm (0.011~ 0.019 in.)
Ring, End Gap: Second Compression0.3~0.5 mm (0.011~0.019 in.)
Piston Pin:
Diameter20.9970~20.9985 mm (0.82665~0.82671 in.)
Pin Offset0.8 mm (0.03 in.) Towards Thrust Side
Clearance: In Piston0.0035~0.0140 mm (0.00013~0.00055 in.)
Clearance: In RodInterference Fit in Rod
Length61.5 mm (2.42 in.)
Camshaft:
Lift – Intake9.2 mm (0.36 in.)
Lift – Exhaust9.2 mm (0.36 in.)
End Play0.040~0.14 mm (0.0015~0.0055 in.)
Bearing Journal OD42.455~43.470 mm (1.6714~1.7114 in.)
Crankshaft:
Main Journal:
Diameter (All)
Out of Round (Maximum)57.974~57.995 mm (2.2824~2.2832 in.)
0.003 mm (0.0001 in.)
Main Bearing Clearance (All)0.015~0.040 mm (0.00059~0.00157 in.)
Crankshaft End Play0.070~0.302 mm (0.0027~0.0118 in.)
Service OversizeAvailable in 2 sizes
0.25 mm and 0.50 mm (0.0098~0.0196 in.)
Connecting Rod Journal:

ENGINE ELECTRICAL 1E – 9
DAEWOO V–121 BL4
STARTER MOTOR NOISE
To correct starter motor noise during starting, use the following procedure:
Checks
Action
Check for a high–pitched whine during cranking, before
the engine fires. The engine cranks and fires properly.The distance is too great between the starter pinion and
the flywheel. Shimming the starter toward the flywheel is
required.
Check for a high–pitched whine after the engine fires, as
the key is being released. The engine cranks and fires
properly. This intermittent complaint is often diagnosed as
”starter hang–in” or ”solenoid weak.”The distance is too small between the starter pinion and
the flywheel. Shimming the starter away from the flywheel
is required.
Check for a loud ”whoop” after the engine fires but while
the starter is still held engaged. The sound is like a siren
if the engine is revved while the starter is engaged.The most probable cause is a defective clutch. A new
clutch will often correct this problem.
Check for a ”rumble,” a ”growl,” or, in severe cases, a
”knock” as the starter is coasting down to a stop after start-
ing the engine.The most probable cause is a bent or unbalanced starter
armature. A new armature will often correct this problem.
If the complaint is noise, correction can be achieved by
proper shimming as follows:
1. Check for a bent or a worn flywheel.
2. Start the engine and carefully touch the outside di-
ameter of the rotating flywheel ring gear with chalk
or a crayon to show the high point of the tooth run-
out. Turn the engine OFF and rotate the flywheel so
that the marked teeth are in the area of the starter
pinion gear.
3. Disconnect the negative battery cable to prevent
cranking the engine.
4. Check the pinion–to–flywheel clearance by using a
wire gauge of 0.5 mm (0.02 inch) minimum thick-
ness (or diameter). Center a pinion tooth between
two flywheel teeth and the gauge. Do not gauge in
the corners, where a misleading larger dimension
may be observed. If the clearance is under this
minimum, shimming the starter away from the fly-
wheel is required.
5. If the clearance approaches 1.5 mm (0.06 inch) or
more, shimming the starter toward the flywheel is
required. This condition is generally the cause of
broken flywheel teeth or the starter housing. Shim
the starter toward the flywheel by shimming only
the outboard starter mounting pad. A shim of 0.40
mm (0.016 inch) thickness at this location will de-
crease the clearance by approximately 0.30 mm
(0.012 inch). If normal starter shims are not avail-
able, plain washers or other suitable material may
be used as shims.BATTERY LOAD TEST
1. Check the battery for obvious damage, such as a
cracked or broken case or cover, which could per-
mit the loss of electrolyte. If obvious damage is
noted, replace the battery.
CAUTION : Do not charge the battery if the hydrome-
ter is clear or light yellow. Instead, replace the battery.
If the battery feels hot, or if violent gassing or spew-
ing of electrolyte through the vent hole occurs, dis-
continue charging or reduce the charging rate to
avoid personal injury.
2. Check the hydrometer. If the green dot is visible, go
to the load test procedure. If the indicator is dark
but green is not visible, charge the battery. For
charging a battery removed from the vehicle, refer
to ”Charging a Completely Discharged Battery” in
this section.
3. Connect a voltmeter and a battery load tester
across the battery terminals.
4. Apply a 300–ampere load for 15 seconds to remove
any surface charge from the battery.
5. Remove the load.
6. Wait 15 seconds to let the battery recover, and ap-
ply a 270–ampere load.
Important : The battery temperature must be estimated
by touch and by the temperature condition the battery has
been exposed for the preceding few hours.
7. If the voltage does not drop below the minimum
listed, the battery is good and should be reinstalled.
If the voltage is less than the minimum listed, re-
place the battery. Refer to ”Battery Specifications”
in this section.

1F – 82IENGINE CONTROLS
DAEWOO V–121 BL4
IDLE AIR CONTROL SYSTEM CHECK (1.8L DOHC)
Circuit Description
The Engine Control Module (ECM) controls the engine idle
speed with the Idle Air Control (IAC) valve. To increase the
idle speed, the ECM pulls the IAC pintle away from its seat,
allowing more air to pass by the throttle body. To decrease
the idle speed, it extends the IAC valve pintle toward its
seat, reducing bypass air flow. A scan tool will read the
ECM commands to the IAC valve in counts. The higher
counts indicate more air bypass (higher idle). The lower
counts indicate less air is allowed to bypass (lower idle).
Diagnostic Aids
If the idle is too high, stop the engine. Fully extend the Idle
Air Control (IAC) valve with a IAC driver. Start the engine.
If the idle speed is above 800 rpm, locate and repair the
vacuum leak. Also, check for a binding throttle plate or
throttle linkage or an incorrect base idle setting.
Test Description
The number(s) below refer to step(s) on the diagnostic
table.
2. The IAC valve is extended and retracted by the IAC
driver. IAC valve movement is verified by an engine
speed change. If no change in engine speed oc-
curs, the valve can be removed from the throttle
body and tested. Connect the IAC driver to the re-
moved IAC valve and turn the ignition ON. Do not
start the engine.5. This step checks the quality of the IAC valve move-
ment in Step 2. Fully extending the IAC valve may
cause an engine stall. This may be normal.
6. Steps 2 and 5 verify proper IAC valve operation.
This step checks the IAC circuit for a wiring or ECM
fault.
Idle Air Control Valve Reset Procedure
Whenever the battery cable or the Engine Control Module
(ECM) connector or the ECM fuse Ef11 is disconnected or
replaced, the following idle learn procedure must be per-
formed:
1. Turn the ignition ON for 5 seconds.
2. Turn the ignition OFF for 10 seconds.
3. Turn the ignition ON for 5 seconds.
4. Start the engine in park/neutral.
5. Allow the engine to run until the engine coolant is
above 185°F (85°C).
6. Turn the A/C ON for 10 seconds, if equipped.
7. Turn the A/C OFF for 10 seconds, if equipped.
8. If the vehicle is equipped with an automatic trans-
axle, apply the parking brake. While pressing the
brake pedal, place the transaxle in D (drive).
9. Turn the A/C ON for 10 seconds, if equipped.
10. Turn the A/C OFF for 10 seconds, if equipped.
11. Turn the ignition OFF. The idle learn procedure is
complete.

1F – 146IENGINE CONTROLS
DAEWOO V–121 BL4
S Damaged harness
Test Description
Number(s) below refer to the step number(s) on the Diag-
nostic Table.
1. The On–Board Diagnostic (EOBD) System Check
prompts the technician to complete some basic
checks and store the freeze frame and failure re-
cords data on the scan tool if applicable. This
creates an electronic copy of the data taken when
the malfunction occurred. The information is then
stored on the scan tool for later reference.
2. This step determines if DTC P0135 is the result of
a hard failure or an intermittent condition. With the
ignition ON, engine OFF, the HO2S1 voltage dis-played on the scan tool should change within sever-
al minutes toward 0 or 1 volt, indicating that the
heater is working properly.
3. Probing terminal 4 of the HO2S1 connector verifies
if voltage is available to the HO2S1 heater.
4. If voltage is available at the connector, than it be-
comes a good voltage source to check for a ground
at terminal 3.
5. Determines if voltage is not available at the HO2S1
due to an open in the HO2S1 fuse or open ignition
feed circuit. If the fuse is open, determine if it was
due to a short in the ignition feed circuit before re-
placing the fuse.
DTC P0135 – Front Heated Oxygen Sensor Heater Circuit Not
Functioning
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Is the check complete?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
2Notice : If the engine has just been operating, allow
the engine to cool for about one–half hour before
proceeding.
1. Turn the ignition switch ON, with the engine
OFF.
2. Install a scan tool.
Does the Front Heated Oxygen Sensor (HO2S1)
voltage gradually change toward the specified volt-
age?0 v or 1 vGo to Step 13Go to Step 3
31. Disconnect the HO2S1 electrical connector.
2. With a test light connected to ground, probe
the ignition feed circuit, terminal 2 of the con-
nector.
Does the test light illuminate?–Go to Step 4Go to Step 5
4Connect a test light between the ignition feed and
ground circuits, terminal 2 and 3 of the connector.
Does the test light illuminate?–Go to Step 6Go to Step 7
5Inspect the fuse in the engine fuse block.
Is the fuse open?–Go to Step 8Go to Step 9
6Check the connections terminal 2 and 1 at the
HO2S2 connector and repair as necessary.
Is a repair necessary?–Go to Step 13Go to Step 10
7Check the connections terminal 4 at the HO2S1 con-
nector and repair as necessary.
Is a repair necessary?–Go to Step 13Go to Step 11
81. Check for a short to ground in the HO2S1 igni-
tion feed circuit and repair as necessary?
2. Replace open fuse.
Is the action complete?–Go to Step 13–

1F – 386IENGINE CONTROLS
DAEWOO V–121 BL4
S Damaged harness
Test Description
Number(s) below refer to the step number(s) on the Diag-
nostic Table.
1. The On–Board Diagnostic (EOBD) System Check
prompts the technician to complete some basic
checks and store the freeze frame and failure re-
cords data on the scan tool if applicable. This
creates an electronic copy of the data taken when
the malfunction occurred. The information is then
stored on the scan tool for later reference.
2. This step determines if DTC P0135 is the result of
a hard failure or an intermittent condition. With the
ignition ON, engine OFF, the HO2S1 voltage dis-played on the scan tool should change within sever-
al minutes toward 0 or 1 volt, indicating that the
heater is working properly.
3. Probing terminal 2 of the HO2S1 connector verifies
if voltage is available to the HO2S1 heater.
4. If voltage is available at the connector, than it be-
comes a good voltage source to check for a ground
at terminal 3.
5. Determines if voltage is not available at the HO2S1
due to an open in the HO2S1 fuse or open ignition
feed circuit. If the fuse is open, determine if it was
due to a short in the ignition feed circuit before re-
placing the fuse.
DTC P0135 – Front Heated Oxygen Sensor (HO2S1) Heater Circuit
Not Functioning
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Is the check complete?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
2Notice : If the engine has just been operating, allow
the engine to cool for about one–half hour before
proceeding.
1. Turn the ignition switch ON, with the engine
OFF.
2. Install a scan tool.
Does the Front Heated Oxygen Sensor (HO2S1)
voltage gradually change toward the specified volt-
age?0 v or 1 vGo to Step 13Go to Step 3
31. Disconnect the HO2S1 electrical connector.
2. With a test light connected to ground, probe
the ignition feed circuit, terminal 4 of the con-
nector.
Does the test light illuminate?–Go to Step 4Go to Step 5
4Connect a test light between the ignition feed and
ground circuits, terminal 4 and 3 of the connector.
Does the test light illuminate?–Go to Step 6Go to Step 7
5Inspect the fuse in the engine fuse block.
Is the fuse open?–Go to Step 8Go to Step 9
6Check the connections terminal 4 and 1 at the
HO2S1 connector and repair as necessary.
Is a repair necessary?–Go to Step 13Go to Step 10
7Check the connections terminal 3 at the HO2S1 con-
nector and repair as necessary.
Is a repair necessary?–Go to Step 13Go to Step 11
81. Check for a short to ground in the HO2S1 igni-
tion feed circuit and repair as necessary?
2. Replace open fuse.
Is the action complete?–Go to Step 13–