2004 DAEWOO LACETTI cooling

ZF 4 HP 16 AUTOMATIC TRANSAXLE 5A1 – 123
DAEWOO V–121 BL4
S The TCM will record operating conditions at the
time the diagnostic fails. This information will be
stored in the Failure Records buffer.
S Adopt Emergency/ Substitute mode and constant
4th gear by hydraulic control.
S After ignition OFF/ON : 3rd gear by hydraulic con-
trol. Possible P, R and N also possible.
S High line pressure
Conditions for Clearing the MIL/DTCS The MIL will turn OFF when the malfunction has
not occurred after three–ignition cycle.
S A history DTC will clear after 40 consecutive warm
up cycles without a fault.
S Using a scan tool can clear history DTCs.
Diagnostic Aids
S Check for intermittent input speed sensor or output
speed sensor circuit problems.
S Check for possible incorrect calibration.
DTC P0734 – Gear 4 Incorrect Ratio
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Is the check completed?–Go to Step 2Go to ”On–
Board Diagnos-
tic System
Check”
2Visually inspect the transaxle cooling system for
fluid leaks.
Was condition found and corrected?–Go to Step 7Go to Step 3
3Has the transaxle fluid checking procedure been
performed?–Go to Step 4Go to Trans-
axle fluid check
procedures
41. Using the scan tool record each transaxle drive
range.
2. Drive the vehicle in transaxle gear ranges 1,2,3
and D with TP greater than 15% and vehicle
speed greater than 16km/h(10mph) for five
seconds.
Does commanded gear ratio match ranges as
shown?1st = 2.719
2nd = 1.487
3rd = 1.000
4th = 0.717Refer to Diag-
nostic AidsGo to Step 5
5Perform line pressure check.
Was the condition found and corrected?–Go to Step 7Go to Step 6
6Check for possible clutch slippage.
Was the condition found and corrected?–Go to Step 7–
71. After the repair, use a scan tool
clear info"
function and road test the vehicle.
2. Review the
DTC info".
Has the last test failed or is the current DTC dis-
played?Replace trans-
axle assemblyRepair verified
exit DTC chart

7A – 6IHEATING AND VENTILATION SYSTEM
DAEWOO V–121 BL4
DIAGNOSIS
HEATER SYSTEM
INSUFFICIENT HEATING OR DEFROSTING
CAUTION : The cooling system is pressurized when hot. Injury can result from removing the surge tank cap be-
fore the engine is sufficiently cool.
Step
ActionValue(s)YesNo
1Verify the customer’s complaint.
Are the customer’s concerns verified?–Go to Step 2System OK
2Check the coolant level.
Is the coolant level correct?–Go to Step 4Go to Step 3
3Add coolant as needed.
Is the repair complete?–System OKGo to Step 4
4Check the timing belt for tension or damage.
Are the drive belts OK?–Go to Step 6Go to Step 5
5Correct any problem with the timing belt.
Is the repair complete?–System OKGo to Step 6
6Check the coolant hoses for leaks or kinks.
Are the coolant hoses OK?–Go to Step 8Go to Step 7
7Repair any problem with the coolant hoses.
Is the repair complete?–System OKGo to Step 8
8Check the surge tank cap. Refer to Section 2D, En-
gine Cooling.
Is the surge tank cap OK?–Go to Step 10Go to Step 9
9Repair or replace the surge tank cap as needed.
Is the repair complete?–System OKGo to Step 10
101. Turn the A/C switch OFF on vehicles equipped
with air conditioning (A/C).
2. Set the blower motor switch on maximum
speed.
3. Set the heater control to full hot.
4. Turn the ignition ON.
5. Check for airflow from the vent outlet.
Is there heavy airflow from the heater outlet?–Go to Step 11Go to Step 26
11Check for a change in the airflow at various blower
speeds.
Does the blower speed increase as the switch is
turned from 1 to 4.–Go to Step 12Go to ”Blower
Electrical
(Manual and
Non–A/C)”
121. Turn the A/C switch OFF.
2. Set the temperature lever to full hot.
3. Set the blower motor switch on maximum
speed.
4. With the engine sufficiently cool, remove the
surge tank cap.
5. Start the vehicle and idle the engine.
6. Watch for the flow of the coolant.
Is the coolant flow visible?–Go to Step 14Go to Step 13

HEATING AND VENTILATION SYSTEM 7A – 7
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
131. Check for the following problems:
S Restriction in the cooling system.
S Failed water pump impeller.
S Faulty thermostat.
2. Make repairs to the cooling system, as needed.
Are the repairs complete?–System OKGo to Step 14
141. Install the surge tank cap.
2. With the ignition ON, allow the engine to warm
up for about 20 minutes. Drive the vehicle at 48
km/h (30 mph).
3. Use a thermometer to measure the ambient air
temperature and the discharge air temperature
at the heater outlet.
Does the heater output meet the minimum values
given?Go to ”Heater
Temperature
Specifications”Go to Step 15Go to Step 16
151. Check the vehicle for cold air leaks at the fol-
lowing locations:
S Dash.
S Heater cases.
S Vents.
2. Check under the seat for obstructions.
3. Repair any leaks or obstructions.
Are the repairs complete?–System OK–
161. Turn the ignition OFF.
2. Turn the temperature control knob to full cold,
then rapidly to full hot.
3. Listen for the sound of the temperature door
slam just before it reaches the end of the travel
range of the control knob.
Does the door slam?–Go to Step 18Go to Step 17
171. Check the following aspects of the temperature
door:
S Travel.
S Cables.
S Linkage.
2. Verify the accuracy of the temperature controls
at full hot.
3. Verify the accuracy of the temperature controls
at full cold.
Is the repair complete?–System OK–
181. Set the temperature control knob to full hot.
2. Start the vehicle.
3. Check the temperature of the heater inlet hose
and the heater outlet hose by feel. The air tem-
perature around the hoses should be at least
29°C (84°F).
Is the heater inlet hose hot and the heater outlet
hose warm?–Go to Step 19Go to Step 22
19Check the thermostat. Refer to 2D, Engine Cooling.
Is the thermostat installed and seated properly?–Go to Step 20Go to Step 21

7A – 8IHEATING AND VENTILATION SYSTEM
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
20Replace the thermostat. Refer to Section 2D, En-
gine Cooling.
Is the repair complete?–System OK–
21Reinstall the thermostat.
Is the repair complete?–System OK–
22Inspect the heater hoses for proper installation.
Are the heater hoses reversed?–Go to Step 23Go to Step 24
23Reinstall the heater hoses properly.
Is the repair complete?–System OK–
241. Back flush the heater core.
2. Drain the cooling system.
3. Replace the coolant.
4. Warm the engine to an average operating tem-
perature.
5. Feel the heater inlet hose and the heater outlet
hose.
Is the heater inlet hose hot and the heater outlet
hose warm?–System OKGo to Step 25
25Replace the heater core.
Is the repair complete?–System OK–
26Recheck the system using the ”Control Settings/
Correct Results” tests. Refer to ”Improper Air Deliv-
ery or No Mode Shift” in this section.
Is the repair complete?–System OKGo to Step 27
27Check for airflow from the defroster or the vent out-
lets.
Is there high airflow from the defroster or vent out-
lets?–Go to Step 28Go to Step 29
281. Check the heater door at the floor and the vent
door to get the proper airflow and to verify
proper operation.
2. Repair as required.
Is the repair complete?–System OK–
29Switch the mode knob to defrost.
Is the defroster airflow OK?–Go to Step 30Go to Step 31
301. Remove the heater outlet and check for ob-
structions.
2. Remove any obstructions in the heater outlet.
Is the repair complete?–System OK–
31Check for airflow change at various blower speeds.
Does the blower speed increase as the control is
turned from 1 to 4?–Go to Step 32Go to ”Blower
Electrical
(Manual and
Non–A/C)”
32Check for obstructions in the system at the blower
inlet and at the air filter, if the vehicle is equipped with
one.
Are there any obstructions?–Go to Step 33Go to Step 34
33Remove the obstructions in the system at the blower
inlet or replace a clogged filter.
Is the repair complete?–System OK–

HEATING AND VENTILATION SYSTEM 7A – 19
DAEWOO V–121 BL4
6. Slide the cable eyelet off the post on the tempera-
ture door lever.
7. Pry off the Clip of the temperature cable.
Installation Procedure
1. Install the temperature control cable eyelet to the
post on the temperature door lever.
2. Install the clip of the temperature cable.
3. Install the temperature control cable eyelet to the
post on the controller.
4. Install the clip of the temperature control cable.
5. Install the mode control cable to the mode door.
6. Insert the center molding into position on the instru-
ment panel.
7. Move the temperature control to verify the smooth
operation and function of the door and the cable.
8. Connect the negative battery cable.
9. Operate the heating and cooling systems to verify
proper function.

HEATING AND VENTILATION SYSTEM 7A – 21
DAEWOO V–121 BL4
5. Gently insert the center molding into position on the
instrument panel.
6. Connect the negative battery cable.
7. Confirm the proper operation of the controller by
moving it through all of the controller’s possible
functioning positions.
CONTROL ASSEMBLY KNOB
LIGHTING
(Left–Hand Drive Shown, Right–Hand Drive Similar)
Removal Procedure
1. Disconnect the negative battery cable.
2. Remove the center molding. Refer to ”Control As-
sembly” in this section.
3. Turn the bulb holder to the left and pull out the bulb.
Installation Procedure
1. Install the bulb into the holder and turn the bulb to
the right.
2. Install the control assembly. Refer to ”Control As-
sembly” in this section.
3. Connect the negative battery cable.
4. Check the knob light for proper operation.
HEATER/AIR DISTRIBUTOR CASE
ASSEMBLY
Removal Procedure
1. Disconnect the negative battery cable.
2. Remove the instrument panel and tie–bar. Refer to
Section 9E, Instrumentation/Driver Information.
3. Drain the cooling system. Refer to Section 1D, En-
gine Cooling.
4. Compress the heater hose clamps at the firewall
and slide the clamps toward the engine.
5. Remove the two heater hoses from the core pipes
at the firewall.

HEATING AND VENTILATION SYSTEM 7A – 23
DAEWOO V–121 BL4
Tighten
Tighten the heater/air distributor case assembly
screws to 4 NSm (35 lb–in).
5. Install the heater/air distributor case assembly
screws at the side of the heater core pipes through
the firewall from the engine compartment side.
Tighten
Tighten the heater/air distributor case assembly
screw to 4 NSm (35 lb–in).
6. Install the two heater hoses.
7. Slide the heater hose clamps into position.
8. Connect the rear duct connector.
9. Install the instrument panel and tie–bar. Refer to
Section 9E, Instrumentation/Driver Information.
10. Fill the cooling system. Refer to Section 1D, Engine
Cooling.
11. Connect the negative battery cable.
12. Operate the controls to verify the proper function of
the heating and ventilation systems.
BLOWER MOTOR
Removal Procedure
1. Disconnect the negative battery cable.
2. Remove the glove box. Refer to Section 9E, Instru-
mentation/Driver Information.
3. Put the floor carpet aside for preventing stain.
4. Disconnect the blower motor electrical connector
and resistor connector.
5. Remove the screws that secure the motor to the
heater/air distributor case.

HEATING AND VENTILATION SYSTEM 7A – 25
DAEWOO V–121 BL4
BLOWER RESISTOR
Removal Procedure
1. Disconnect the negative battery cable.
2. Remove the glove box. Refer to Section 9E, Instru-
mentation/Driver Information.
3. Disconnect the electrical connector at the resistor.
4. Remove the mount screws from the resistor.
5. Remove the resistor from the heater/air distributor
case by gently pulling the resistor downward.
Installation Procedure
1. Install the resistor into the heater/air distributor
case with the screws.
Tighten
Tighten the blower motor resistor screws to 1.2 NSm
(11 lb–in).
2. Connect the electrical connector at the resistor.
3. Connect the negative battery cable.
4. Confirm the proper performance of the blower.
5. Replace the glove box. Refer to Section 9E, Instru-
mentation/Driver Information.
HEATER HOSES
Removal Procedure
1. Partially drain the cooling system.
2. Raise and suitably support the vehicle.
3. Compress and slide rearward the two heater hose
spring clamps at the firewall.
4. Gently twist the hose from the left to the right and
back again to loosen the bond between the hose
and the tube.
5. Remove the end of the hose from the tube.
6. Repeat Steps 3 and 4 with the other hose.
7. Compress the heater hose spring clamp on the inlet
coolant line and slide the clamp rearward.
8. Remove the inlet heater hose from the vehicle.
9. Compress the heater hose spring clamp on the out-
let coolant line and slide the clamp backward.
10. Remove the outlet heater hose from the vehicle.