2004 DAEWOO LACETTI Rod

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.

ZF 4 HP 16 AUTOMATIC TRANSAXLE 5A1 – 47
DAEWOO V–121 BL4
Repairing the Fluid Leak
Once the leak point is found the source of the leak must
be determined. The following list describes the potential
causes for the leak:
S Fasteners are not torqued to specification.
S Fastener threads and fastener holes are dirty or
corroded.
S Gaskets, seals or sleeves are misarranged, dam-
aged or worn.
S Damaged, warped or scratched seal bore or gasket
surface.
S Loose or worn bearing causing excess seal or
sleeve wears.
S Case or component porosity.
S Fluid level is too high.
S Plugged vent or damaged vent tube.
S Water or coolant in fluid.
S Fluid drain back holes plugged.
ELECTRICAL/GARAGE SHIFT TEST
This preliminary test should be performed before a hoist
or road test to make sure electronic control inputs is con-
nected and operating. If the inputs are not checked before
operating the transaxle, a simple electrical condition could
be misdiagnosed as a major transaxle condition.
A scan tool provides valuable information and must be
used on the automatic transaxle for accurate diagnosis.
1. Move gear selector to P (Park) and set the parking
brake.
2. Connect scan tool to Data Link Connector (DLC)
terminal.
3. Start engine.
4. Turn the scan tool ON.
5. Verify that the appropriate signals are present.
These signals may include:
S ENGINE SPEED
S VEHICLE SPEED
S THROTTLE POSITION
S TRANSAXLE GEAR STATE
S GEAR SHIFT LEVER POSITION
S TRANSAXLE FLUID TEMPERATURE
S CLOSED THROTTLE POSITION LEARN
S OPEN THROTTLE POSITION LEARNT
S CLOSED ACCEL. PEDAL POSITION LEARNT
S OPEN ACCEL. PEDAL POSITION LEARNT
S A/C COMPRESSOR STATUS
S MODE SWITCH
S THROTTLE POSITION VOLTAGE
S GEAR SHIFT LEVER POSITION VOLTAGE
S TRANS. FLUID TEMPERATURE VOLTAGE
S A/C SWITCH
S MODE SWITCH VOLTAGE
S BATTERY VOLTAGE
6. Monitor the A/C COMPRESSOR STATUS signal
while pushing the A/C switch.S The A/C COMPRESSOR STATUS should come
ON when the A/C switch is pressed, and turns
OFF when the A/C switch is repushed.
7. Monitor the GEAR SHIFT LEVER POSITION signal
and move the gear shift control lever through all the
ranges.
S Verify that the GEAR SHIFT LEVER POSITION
value matches the gear range indicated on the
instrument panel or console.
S Gear selections should be immediate and not
harsh.
8. Move gear shift control lever to neutral and monitor
the THROTTLE POSITION signal while increasing
and decreasing engine speed with the accelerator
pedal.
S THROTTLE POSITION should increase with
engine speed.
ROAD TEST PROCEDURE
S Perform the road test using a scan tool.
S This test should be performed when traffic and road
conditions permit.
S Observe all traffic regulations.
The TCM calculates upshift points based primarily on two
inputs : throttle angle and vehicle speed. When the TCM
wants a shift to occur, an electrical signal is sent to the shift
solenoids which in turn moves the valves to perform the
upshift.
The shift speed charts reference throttle angle instead of
”min throttle” or ”wot” to make shift speed measurement
more uniform and accurate. A scan tool should be used to
monitor throttle angle. Some scan tools have been pro-
grammed to record shift point information. Check the
introduction manual to see if this test is available.
Upshift Procedure
With gear selector in drive(D)
1. Look at the shift speed chart contained in this sec-
tion and choose a percent throttle angle of 10 or
25%.
2. Set up the scan tool to monitor throttle angle and
vehicle speed.
3. Accelerate to the chosen throttle angle and hold the
throttle steady.
4. As the transaxle upshifts, note the shift speed and
commanded gear changes for :
S Second gear.
S Third gear.
S Fourth gear.
Important : Shift speeds may vary due to slight hydraulic
delays responding to electronic controls. A change from
the original equipment tire size affects shift speeds.
Note when TCC applies. This should occur in fourth gear.
If the apply is not noticed by an rpm drop, refer to the
”Lock–up Clutch Diagnosis” information contained in this
section.

5A1 – 56IZF 4 HP 16 AUTOMATIC TRANSAXLE
DAEWOO V–121 BL4
SYMPTOM DIAGNOSIS
Oil Leakage
Notice :
– Careful localization of leakage points may make it
possible to prevent incorrect or cost–intensive re-
pairs.
Test Steps :– Thoroughly clean the transaxle, engine, and sur-
rounding area(using a steam jet, for example).
– To locate leakage, use a suitable identifying spray
or similar product.
– Depending on the amount of leakage, take the
car for a short or a longer test drive – It may prove
sufficient to place the car on a hoist and run the
engine at idle speed to trace the leak.
– If possible, determine exactly which type of oil is
escaping.
Symptom
Possible CauseAction
Transaxle Oil Leak-
ageOil Pump(Torque Converter Sealing)S Visually check torque converter sealing.
S Replace the converter sealing as described in
the transaxle repair on the vehicle service.
Crankshaft Sealing RingS Check whether engine oil or TFT is leaking out.
S If leak is engine oil, replace the sealing ring as
described in the engine repair instruction.
Torque ConverterS Visual check.
S Fit an exchange converter as described in the
repair instruction.
Oil Content Too HighS Check oil level(TFT and axle oil) as described
in this chapter.
S Correct oil level, and recheck after a test drive.
Notice : Comply with the measuring procedure (fill-
ing procedure) in the repair instruction. Check the oil
level at the overflow plug adjust to proper level if nec-
essary.
O–ring at Bolt Head Damaged or Miss-
ingS Check O–ring.
S Replace O–ring as described in the repair in-
struction.
Shaft SealS Visually check the shaft seal.
S Replace the sealing ring as described in the
repair instruction.
Hose Clamp LooseS Check to ensure that the hose clamp fits tightly.
S If necessary, retighten clamp.
Oil Pan Gasket Not Installed ProperlyS Check to see if the gasket was positioned
properly.
S Install gasket properly as described in the re-
pair instruction.
Oil Pan Gasket DamagedS Check the gasket visually.
S Replace gasket as described in the repair in-
struction.
Bolt at Bracket LooseCheck the Tightening Torque
Retighten bolt
Sealing Ring at Oil DipstickS Check O–ring.
S If necessary, replace O–ring.
Sealing Ring Near End–Cover Connec-
tion DefectiveS Check sealing rings.
S Put in new sealing ring Check O–ring as de-
scribed in the repair instruction.

ZF 4 HP 16 AUTOMATIC TRANSAXLE 5A1 – 57
DAEWOO V–121 BL4
Symptom ActionPossible Cause
Sealing Ring Selector ShaftS Check sealing ring.
S Replace sealing ring as described in the repair
instruction.
O–ring at Socket OutletS Check O–ring.
S Replace O–ring as described in the repair in-
struction.
O–ring and Speed Sensor ConnectionS Check O–ring.
S Replace O–ring as described in the repair in-
struction.
Oil Leak Incorrectly IdentifiedS No oil leak is possible at this point.
Speed Sensor Itself Is LeakingS Check speed sensor.
S Replace speed sensor as described in the re-
pair instruction.
Hair Line Crack at the Piping in the Con-
nection Area, Sealing Ring Fit in Trans-
axle HousingS Pressurize the line with compressed air and
check it.
S Replace lines as described in the repair in-
struction.
O–ring Defective, IncorrectCheck O–ring.
Replace O–rings as described in the repair instruc-
tion.
Plug LooseCheck the Tightening Torque for the screw plug.
Tighten to torque specified in the repair instruction.
Noise
SymptomPossible CauseAction
NoiseTFT Level Too LowS When the TFT level is too low, the gear wheels
from the transaxle oil pump might generate
noise.
S Check the TFT level as described in the repair
instruction and fill to the proper level.
Monolith in Catalytic Converter Has
BrokenS Check according to the exhaust gas diagnostic
procedure or by shaking the catalytic converter
casing.
S Replace catalytic converter if necessary.
Noise from Auxiliaries (e.g. exhaust
system, alternator, drive shafts.)S Check these components; if necessary, elimi-
nate the faults as described in the repair in-
struction
Noise from Tires or Wheel BearingsS Eliminate fault if necessary
Noise from Planetary GearsS Whistling noise on traction and overrun(in first
gear only)caused by high rotating speeds(func-
tionally unavoidable)
Cumulative Tooth Backlash in the Com-
plete Drive LineS Production status. Customer must be con-
vinced.
Jerky Noise of the Parking Lock (e.g.
when the car is standing on a gradient)S Load–reversal reaction
S Apply the handbrake before selection the park-
ing Lock (position P)

5A1 – 58IZF 4 HP 16 AUTOMATIC TRANSAXLE
DAEWOO V–121 BL4
Symptom ActionPossible Cause
NoiseThe Engine’s Torsional Vibrations are
Being Transmitted to the Drive ShaftsS At low speeds in fourth gear, vibration can
arise (driving at too low an engine speed)
S Noise is functionally unavoidable; due to toler-
ances. Convince the customer.
NoiseTorque Reaction Strut LooseS Check mounting and repair if necessary.
Shift quality
Notice :
– The assessment of shaft quality is, to a large ex-
tent, an individual, subjective matter. Take careful
note of how the customer describes the complaint
and of the manner in which he or she handles the
vehicle and the controls.
– A sudden deterioration of shift quality may also
be caused by the transaxle selecting an emergency
or substitute program
Test Steps :– Carry out the general checks described in the
automatic transaxle diagnostic information.
– Perform a test drive to answer the following ques-
tions.
In which driving situations does the shift quality
complaint arise?
To which shifts does the complaint apply?
Is the complaint reproducible within a short period,
or has it only occurred sporadically or on a single
occasion?
– Check the oil level and oil quality
– Interrogate the fault memory and read out mea-
surement block data.
Symptom
Possible CauseAction
Shift QualityRapid Pressure Build–up in the ClutchS Operating error (position selected several times
in quick succession).
Jerk When Parking Lock Is ReleasedS Refer to ”Noise” in this section.
Incorrect Electronic Transaxle Control
moduleS Check the data status for transaxle control
module ; refer to ”TCM” in this section.
Emergency/Substitute Program Has
Been ActivatedS For checking and remedial action, refer to
”Emergency/Substitute program” in this sec-
tion.
Accelerator Pedal in Indefinite Position
Between Full Throttle and Kick DownS Persuade customer to choose clearly between
kick down and full throttle
S Check setting according go engine repair in-
struction ; adjust if necessary.
Control Overlap Between to Clutches
During ShiftS Production status
S Convince the customer
Temperature Sensor
(Not Fault Memory)S Check function according to ”Emergency/Sub-
stitute program” in this section.
Kick Down Setting IncorrectS Check
A) Floor mat is obstructing accelerator pedal
B) The kick down setting as described in the
Engine Section.
Malfunction
Notice :
The faults dealt with here concern transaxle functions
such as ”traction” (forwards and reverse) and all type of
shifts. Entries will not always be made in the fault memory.Test Steps :
Perform the general checks according to the automatic
transaxle diagnostic procedure.
– Test drive
– Check oil level and quality
– Interrogate fault memory

ZF 4 HP 16 AUTOMATIC TRANSAXLE 5A1 – 193
DAEWOO V–121 BL4
Repairing the Fluid Leak
The following are potential causes for fluid leaks. Check
and repair, as necessary.
S Fasteners are not tightened to specifications.
S Fastener threads and tapped holes are dirty or cor-
roded.
S Gaskets, seals or sleeves are misaligned, dam-
aged, or warped, or scratched.
S The manual shaft is nicked or damaged.
S There is a loose or worn bearing causing excess
seal or sleeve wear.
S Case or component porosity.
S The fluid level is too high.
S There is a plugged vent or a damaged vent tube.
S There is water or coolant in the fluid.
S Fluid drain back holes are plugged.
CASE POROSITY REPAIR
CAUTION : Epoxy adhesive may cause skin irritations
and eye damage. Read and follow all information on
the container label as provided by the manufacturer.
1. Thoroughly clean the area to be repaired with a
cleaning solvent. Air dry the area.
2. Using instructions from the manufacturer, mix a
sufficient amount of epoxy to make the repair.
3. While the transaxle case is still hot, apply the
epoxy. You can use a clean, dry soldering acid
brush to clean the area and also apply the epoxy
cement. Make certain that the area to be repaired is
fully covered.
4. Allow the epoxy cement to dry for 3 hours before
starting the engine.
5. Repeat the fluid leak diagnosis procedures. Refer
to ”Fluid Leak Diagnosis and Repair” in this sec-
tion.
SHIFT CONTROL LEVER ASSEMBLY
Removal Procedure
1. Disconnect the negative battery cable.
2. Remove the floor console. Refer to Section 9G,
Interior Trim.
3. Disconnect the electrical switch connectors.

5A2 – 20IAISIN AUTOMATIC TRANSAXLE
DAEWOO V–121 BL4
1. Transaxle Housing
2. Oil Seal
3. Oil Reservoir Plate
4. Transaxle Oil Apply Pipe
5. Differential Gear Oil Apply Pipe
6. Transaxle Oil Apply Pipe Clamp
7. Spring
8. Check Valve Pipe Clamp
9. Apply Gasket
10. Brake Drun Gasket
11. Transaxle Wire
12. O–ring
13. Valve Body
14. Parking Lock Pawl
15. Parking Lock Pawl Shaft
16. Torsion Spring
17. Manual Valve lever Shaft
18. Manual Valve Lever
19. Parking Lock Rod
20. Parking Lock Pawl Bracket
21. Manual Detent Spring
22. Pin
23. Spacer24. Oil Seal
25. Transmission Range (TR) Switch
26. Lock Washer
27. Control Lever
28. Washer
29. Gasket
30. Oil Strainer
31. Oil Pan
32. Gasket
33. Magnet
34. Direct Clutch Accumulator Piston
35. O–ring
36. Spring
37. O–ring
38. Forward Clutch Accumulator Piston
39. O–ring
40. Spring
41. O–ring
42. Overdrive Brake Accumulator Piston
43. O–ring
44. O–ring
45. Spring

AISIN AUTOMATIC TRANSAXLE 5A2 – 27
DAEWOO V–121 BL4
WIRING HARNESS AND
CONNECTOR INSPECTION
1. Reproducing test
Perform symptom simulation test on the basis of
user’s condition. Refer to the below factors.
S Occuring–road condition, speed, accelerate,
reduce speed, straight, curve, air temperature,
weather, etc.
2. Inspect the connection condition of between con-
nectors.
Inspect the failure between connectors by visual
check and contact pressure check.
S Connector disconnected
S Terminals rusted
S Terminals deformation or loose fit
3. Inspect the Continuity of the wiring harness.
Disconnect both ends connector of wiring har-
ness, measure resistance between one connec-
tor terminal and other.
S Normal : 1Ω or less (No open circuit)
S Abnormal :
Ω (Open circuit)
Notice : Measure the resistance while slightly shaking
wire harness vertically and horizontally.
It is rare case wiring harness is broken at the middle of it,
and most cases occur at the connector.
4. Inspect the short circuit of the wiring harness.
Disconnect the connectors of the wiring harness
at both ends, measure resistance between the
applicable terminals of the connector and body
earth.
S Normal : 1M Ω or higher (No short circuit)
S Abnormal : Low resistance (Short circuit)Measure the resistance between one terminal
an another terminal in the same connector.(Ex-
cept between power supply or between earth).
S Normal : 1M Ω or higher (No short circuit)
S Abnormal : Low resistance (Short circuit)
Notice : Measure the wiring harness while slightly shaking
vertically and horzontally.
It is usual case of the short circuit that wiring harness is
crowded body and clamping failure.
5. Temporary connection failure of the connector.
It is thought that temporally the connection fail-
ure of the connector is cause when you can not
decide cause of DTC detection.
Therfore make sure to inspect and clean the
connector and delete the memorized DTC.
ROAD TEST
Road test is to diagnosis failure symptom accurately and
check the failure symptom after procedure.
Confirm whether below condition before road test. Oil tem-
perature is hot condition (50°C (122°F) ~ 80°C (176°F)).
1. D range test
S Check for up–shift, down–shift, kick–down and
lock–up operation at the shift point shown in the
shift schedule.
S Check for engine brake operation.
S Check for Check abnormal shock, noise and
harshness.
2. ”P” range test
Park vehicle on a gradient (more than 5°), shift
into the ”P” range and release parking brake.
Then, check to see no moving vehicle by opera-
tion of parking lock pawl.