2004 DAEWOO LACETTI Resistance vs temperature

ENGINE CONTROLS 1F – 625
DAEWOO V–121 BL4
EVAPORATIVE EMISSION CANISTER
The Evaporative (EVAP) Emission canister is an emission
control device containing activated charcoal granules.
The EVAP emission canister is used to store fuel vapors
from the fuel tank. Once certain conditions are met, the en-
gine control module (ECM) activates the EVAP canister
purge solenoid, allowing the fuel vapors to be drawn into
the engine cylinders and burned.
POSITIVE CRANKCASE
VENTILATION SYSTEM OPERATION
A Positive Crankcase Ventilation (PCV) system is used to
provide complete use of the crankcase vapors. Fresh air
from the air cleaner is supplied to the crankcase. The fresh
air is mixed with blowby gases which are then passed
through a vacuum hose into the intake manifold.
Periodically inspect the hoses and the clamps. Replace
any crankcase ventilation components as required.
A restricted or plugged PCV hose may cause the following
conditions:
S Rough idle
S Stalling or low idle speed
S Oil leaks
S Oil in the air cleaner
S Sludge in the engine
A leaking PCV hose may cause the following conditions:
S Rough idle
S Stalling
S High idle speed
ENGINE COOLANT TEMPERATURE
SENSOR
The Engine Coolant Temperature (ECT) sensor is a
thermistor (a resistor which changes value based on tem-
perature) mounted in the engine coolant stream. Low cool-
ant temperature produces a high resistance (100,000
ohms at –40 °F [–40 °C]) while high temperature causes
low resistance (70 ohms at 266 °F [130 °C]).
The engine control module (ECM) supplies 5 volts to the
ECT sensor through a resistor in the ECM and measures
the change in voltage. The voltage will be high when the
engine is cold, and low when the engine is hot. By measur-
ing the change in voltage, the ECM can determine the
coolant temperature. The engine coolant temperature af-
fects most of the systems that the ECM controls. A failure
in the ECT sensor circuit should set a diagnostic trouble
code P0117 or P0118. Remember, these diagnostic
trouble codes indicate a failure in the ECT sensor circuit,
so proper use of the chart will lead either to repairing a wir-
ing problem or to replacing the sensor to repair a problem
properly.
THROTTLE POSITION SENSOR
The Throttle Position (TP) sensor is a potentiometer con-
nected to the throttle shaft of the throttle body. The TP sen-
sor electrical circuit consists of a 5 volt supply line and a
ground line, both provided by the engine control module
(ECM). The ECM calculates the throttle position by moni-
toring the voltage on this signal line. The TP sensor output
changes as the accelerator pedal is moved, changing the
throttle valve angle. At a closed throttle position, the output
of the TP sensor is low, about 0.5 volt. As the throttle valve
opens, the output increases so that, at Wide Open Throttle
(WOT), the output voltage will be about 5 volts.
The ECM can determine fuel delivery based on throttle
valve angle (driver demand). A broken or loose TP sensor
can cause intermittent bursts of fuel from the injector and
an unstable idle, because the ECM thinks the throttle is
moving. A problem in any of the TP sensor circuits should
set a diagnostic trouble code (DTC) P0121 or P0122.
Once the DTC is set, the ECM will substitute a default val-
ue for the TP sensor and some vehicle performance will
return. A DTC P0121 will cause a high idle speed.
CATALYST MONITOR OXYGEN
SENSORS
Three–way catalytic converters are used to control emis-
sions of hydrocarbons (HC), carbon monoxide (CO), and
oxides of nitrogen (NOx). The catalyst within the convert-
ers promotes a chemical reaction. This reaction oxidizes
the HC and CO present in the exhaust gas and converts
them into harmless water vapor and carbon dioxide. The
catalyst also reduces NOx by converting it to nitrogen. The
engine control module (ECM) can monitor this process us-
ing the HO2S1 and HO2S2 sensor. These sensors pro-
duce an output signal which indicates the amount of oxy-
gen present in the exhaust gas entering and leaving the
three–way converter. This indicates the catalyst’s ability to
efficiently convert exhaust gasses. If the catalyst is operat-
ing efficiently, the HO2S1 sensor signals will be more ac-
tive than the signals produced by the HO2S2 sensor. The
catalyst monitor sensors operate the same way as the fuel
control sensors. The sensor’s main function is catalyst
monitoring, but they also have a limited role in fuel control.
If a sensor output indicates a voltage either above or below
the 450 mv bias voltage for an extended period of time, the
ECM will make a slight adjustment to fuel trim to ensure
that fuel delivery is correct for catalyst monitoring.
A problem with the HO2S1 sensor circuit will set DTC
P0131, P0132, P0133 or P0134 depending, on the special
condition. A problem with the HO2S2 sensor signal will set
DTC P0137, P0138, P0140 or P0141, depending on the
special condition.
A fault in the Rear Heated Oxygen Sensor (HO2S2) heat-
er element or its ignition feed or ground will result in lower
oxygen sensor response. This may cause incorrect cata-
lyst monitor diagnostic results.

1F – 626IENGINE CONTROLS
DAEWOO V–121 BL4
EXHAUST GAS RECIRCULATION
VA LV E
The Exhaust Gas Recirculation (EGR) system is used on
engines equipped with an automatic transaxle to lower
NOx (oxides of nitrogen) emission levels caused by high
combustion temperature. The EGR valve is controlled by
the engine control module (ECM). The EGR valve feeds
small amounts of exhaust gas into the intake manifold to
decrease combustion temperature. The amount of ex-
haust gas recirculated is controlled by variations in vacu-
um and exhaust back pressure. If too much exhaust gas
enters, combustion will not take place. For this reason,
very little exhaust gas is allowed to pass through the valve,
especially at idle.
The EGR valve is usually open under the following condi-
tions:
S Warm engine operation.
S Above idle speed.
Results of Incorrect Operation
Too much EGR flow tends to weaken combustion, causing
the engine to run roughly or to stop. With too much EGR
flow at idle, cruise, or cold operation, any of the following
conditions may occur:
S The engine stops after a cold start.
S The engine stops at idle after deceleration.
S The vehicle surges during cruise.
S Rough idle.
If the EGR valve stays open all the time, the engine may
not idle. Too little or no EGR flow allows combustion tem-
peratures to get too high during acceleration and load con-
ditions. This could cause the following conditions:
S Spark knock (detonation)
S Engine overheating
S Emission test failure
INTAKE AIR TEMPERATURE
SENSOR
The Intake Air Temperature (IAT) sensor is a thermistor,
a resistor which changes value based on the temperature
of the air entering the engine. Low temperature produces
a high resistance (4,500 ohms at –40°F [–40°C]), while
high temperature causes a low resistance (70 ohms at
266°F [130°C]).
The engine control module (ECM) provides 5 volts to the
IAT sensor through a resistor in the ECM and measures
the change in voltage to determine the IAT. The voltage will
be high when the manifold air is cold and low when the air
is hot. The ECM knows the intake IAT by measuring the
voltage.
The IAT sensor is also used to control spark timing when
the manifold air is cold.
A failure in the IAT sensor circuit sets a diagnostic trouble
code P0112 or P0113.
IDLE AIR CONTROL VALVE
Notice : Do not attempt to remove the protective cap to
readjust the stop screw. Misadjustment may result in dam-
age to the Idle Air Control (IAC) valve or to the throttle
body.
The IAC valve is mounted on the throttle body where it
controls the engine idle speed under the command of the
engine control module (ECM). The ECM sends voltage
pulses to the IAC valve motor windings, causing the IAC
valve pintle to move in or out a given distance (a step or
count) for each pulse. The pintle movement controls the
airflow around the throttle valves which, in turn, control the
engine idle speed.
The desired idle speeds for all engine operating conditions
are programmed into the calibration of the ECM. These
programmed engine speeds are based on the coolant
temperature, the park/neutral position switch status, the
vehicle speed, the battery voltage, and the A/C system
pressure (if equipped).
The ECM ”learns” the proper IAC valve positions to
achieve warm, stabilized idle speeds (rpm) desired for the
various conditions (park/neutral or drive, A/C on or off, if
equipped). This information is stored in ECM ”keep alive”
memories. Information is retained after the ignition is
turned OFF. All other IAC valve positioning is calculated
based on these memory values. As a result, engine varia-
tions due to wear and variations in the minimum throttle
valve position (within limits) do not affect engine idle
speeds. This system provides correct idle control under all
conditions. This also means that disconnecting power to
the ECM can result in incorrect idle control or the necessity
to partially press the accelerator when starting until the
ECM relearns idle control.
Engine idle speed is a function of total airflow into the en-
gine based on the IAC valve pintle position, the throttle
valve opening, and the calibrated vacuum loss through ac-
cessories. The minimum throttle valve position is set at the
factory with a stop screw. This setting allows enough air-
flow by the throttle valve to cause the IAC valve pintle to
be positioned a calibrated number of steps (counts) from
the seat during ”controlled” idle operation. The minimum
throttle valve position setting on this engine should not be
considered the ”minimum idle speed,” as on other fuel in-
jected engines. The throttle stop screw is covered with a
plug at the factory following adjustment.
If the IAC valve is suspected as the cause of improper idle
speed, refer to ”Idle Air Control System Check” in this sec-
tion.
MANIFOLD ABSOLUTE PRESSURE
SENSOR
The Manifold Absolute Pressure (MAP) sensor measures
the changes in the intake manifold pressure which result
from engine load and speed changes. It converts these to
a voltage output.

5A1 – 52IZF 4 HP 16 AUTOMATIC TRANSAXLE
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
81. Disconnect the internal transaxle harness from
the pressure control valve 4(EDS 4).
2. Measure the resistance of the EDS 4.
Is the resistance within the values shown?Refer to Com-
ponent Resist-
ance ChartGo to Step 20Go to Step 22
9Measure the resistance between terminals 5 and 10
the transaxle wiring connector(EDS 5).
Is the resistance within the values shown?Refer to Com-
ponent Resist-
ance ChartGo to Step 11Go to Step 10
101. Disconnect the internal transaxle harness from
the pressure control valve 5(EDS 5).
2. Measure the resistance of the EDS 5.
Is the resistance within the values shown?Refer to Com-
ponent Resist-
ance ChartGo to Step 20Go to Step 22
11Measure the resistance between terminals 5 and 11
the transaxle wiring connector(EDS 6).
Is the resistance within the values shown?Refer to Com-
ponent Resist-
ance ChartGo to Step 13Go to Step 12
121. Disconnect the internal transaxle harness from
the pressure control valve 6(EDS 6).
2. Measure the resistance of the EDS 6.
Is the resistance within the values shown?Refer to Com-
ponent Resist-
ance ChartGo to Step 20Go to Step 22
13Measure the resistance between terminals 4 and 9
the transaxle wiring connector(transaxle tempera-
ture sensor).
Is the resistance within the values shown?Refer to Com-
ponent Resist-
ance ChartGo to Step 15Go to Step 14
141. Disconnect the internal transaxle harness from
the transaxle temperature sensor.
2. Measure the resistance of the transaxle tem-
perature sensor.
Is the resistance within the values shown?Refer to Com-
ponent Resist-
ance ChartGo to Step 20Go to Step 22
15Measure the resistance between terminals 15 and
16 the transaxle wiring connector(transaxle input
speed sensor).
Is the resistance within the values shown?Refer to Com-
ponent Resist-
ance ChartGo to Step 17Go to Step 16
161. Disconnect the internal transaxle harness from
the transaxle input speed sensor.
2. Measure the resistance of the input speed sen-
sor.
Is the resistance within the values shown?Refer to Com-
ponent Resist-
ance ChartGo to Step 20Go to Step 22
17Measure the resistance between terminals 1 and 2
the transaxle wiring connector(transaxle output
speed sensor).
Is the resistance within the values shown?Refer to Com-
ponent Resist-
ance ChartGo to Step 19Go to Step 18
181. Disconnect the internal transaxle harness from
the transaxle output speed sensor.
2. Measure the resistance of the transaxle output
speed sensor.
Is the resistance within the values shown?Refer to Com-
ponent Resist-
ance ChartGo to Step 20Go to Step 22
19Measure the resistance between terminals of inter-
nal wiring harness.
Is the resistance within the values shown?Refer to Com-
ponent Resist-
ance ChartNo problem
found, exit
tableGo to Step 21

5A1 – 54IZF 4 HP 16 AUTOMATIC TRANSAXLE
DAEWOO V–121 BL4
TRANSAXLE WIRING HARNESS
CONNECTOR
Wiring Harness Connector
Pin numberDescription
1Output Speed Sensor (+)
2Output Speed Sensor (–)
3Solenoid Valve (+)
4Transmission Fluid Temperature Sensor (–)
5Pressure Control Solenoid Valve (+)
6Pressure Control Solenoid Valve (EDS3)
7Pressure Control Solenoid Valve (EDS4)
8Not Used
9Transmission Fluid Temperature Sensor (+)
10Pressure Control Valve Solenoid Valve (EDS5)
11Pressure Control Valve Solenoid Valve (EDS6)
12Solenoid Valve 1
13Solenoid Valve 2
14Not Used
15Input Speed Sensor (–)
16Input Speed Sensor (+)
Component Resistance Chart
ComponentPass
Through
PinsResistance
20°C (68°F)
OhmsResistance w140°C
(212°F) Ohms
Solenoid 13, 1226.5± 0.5Ω26–345 Ω (not relative to temperature)
Solenoid 23, 1326.5± 0.5Ω26–345 Ω (not relative to temperature)
Pressure Control
Solenoid Valve (EDS3)5, 65.7± 0.45Ω5.3–6.3 Ω (not relative to temperature)
Pressure Control
Solenoid Valve (EDS4)5, 75.7± 0.45Ω5.3–6.3 Ω (not relative to temperature)
Pressure Control
Solenoid Valve (EDS5)5, 105.7± 0.45Ω5.3–6.3 Ω (not relative to temperature)

ZF 4 HP 16 AUTOMATIC TRANSAXLE 5A1 – 55
DAEWOO V–121 BL4
Component Resistance w140°C
(212°F) Ohms Resistance
20°C (68°F)
Ohms Pass
Through
Pins
Pressure Control
Solenoid Valve (EDS6)5, 115.7± 0.45Ω5.3–6.3 Ω (not relative to temperature)
Transaxle Temperature Sensor*4, 9980–1,000 Ω
Input Speed Sensor15, 16830 ± 5 Ω788–871 Ω (not relative to tempera-
ture)
Output Speed Sensor*1, 2


* The resistance of the transaxle is necessarily dependent on the temperature.

ZF 4 HP 16 AUTOMATIC TRANSAXLE 5A1 – 89
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE(DTC) P0710
TRANSMISSION FLUID TEMPERATURE SENSOR
CIRCUIT MALFUNCTION
Circuit Description
The TFT sensor is a positive temperature coefficient
thermistor (temperature sensitive resistor) that provides
information to the TCM regarding transaxle fluid tempera-
ture. The temperature sensor is located in valve body. Cal-
culated temperature is a factor used to determine the shift
time and shift delay time.
The internal electrical resistance of the sensor varies in
relation to the operating temperature of the transaxle fluid.
The TCM sends a 5 volt–reference signal to the tempera-
ture sensor and measures the voltage rise in the electrical
circuit. A higher fluid temperature creates a higher resist-
ance in the temperature sensor, thereby measuring a
higher voltage signal.
The TCM measures this voltage as another input to help
control line pressure, shift schedules and TCC apply.
When transaxle fluid temperature reaches 120°C (248°F)
the TCM enters ”hot mode.” Above this temperature the
TCM modifies transaxle shift schedules and TCC apply in
an attempt to reduce fluid temperature by reducing trans-
axle heat generation.Conditions for Setting The DTC
S The calculated temperature is compared with the
predetermined min. and max. value.
S If the temperature is less than min. value or greater
than max value then the current temperature is re-
garded as of range and the corresponding error but
will be set.
S Transmission fluid temperature is not between
–40°C (–40°F) and 150°C (302°F).
Action Taken When The DTC Sets
S No lamp control required but diagnostic information
should be stored immediately when malfunction is
defected.
S TCM assumes the transaxle fluid temperature is
60°C.
S No influence on drivability.
Conditions for Clearing the MIL/DTC
S Using a scan tool can clear history DTCs.
Diagnostic Aids
S When DTC P0710 sets, the possible cause of fault
could be Transmission Temperature Sensor.

5A1 – 90IZF 4 HP 16 AUTOMATIC TRANSAXLE
DAEWOO V–121 BL4
DTC P0710 – Transmission Fluid Temperature Sensor Circuit
Malfunction
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”
21. Install the scan tool.
2. Turn the ignition ON, with the engine OFF.
3. Record then clear DTC(s) and turn the ignition
OFF, then turn the ignition ON.
4. Select TFT on the scan tool.
5. Drive the vehicle and observe the scan tool for
either of the flowing conditions:
6. The TFT does not change more than 1.5°C
(34.7°F) in 80 seconds since start–up.
7. The TFT changes more than 20°C (68°F) with-
in 7 seconds (unrealistic change).
Did either of the fail conditions occur?–Go to Step 3Go to ”Diag-
nostic Aids”
31. Turn the ignition OFF.
2. Disconnect the transaxle wiring connector.
3. Measure the resistance between terminals 9
and 4 of the transaxle wiring connector.
Is the resistance within the values shown?TFT 25°C
990 ΩGo to Step 7Go to Step 4
41. Remove the oil pan.
2. Disconnect the wiring connector of the trans-
axle fluid temperature sensor.
3. Inspect the automatic transaxle wiring harness
for an intermittent short or open.
Was a problem found?–Go to Step 5Go to Step 6
5Replace the automatic transaxle wiring harness.
Is the replacement complete?–System OK–
6Replace the TFT sensor.
Is the action complete?–System OK–
71. Disconnect the automatic transaxle wiring con-
nector and disconnect the wiring connector of
the TCM(transaxle control module).
2. Measure the resistance between terminal 4 of
the transaxle wiring connector and terminal B1
of the TCM wiring connector.
3. Measure the resistance between terminal 9 of
the transaxle wiring connector and terminal A4
of the TCM wiring connector.
Is the resistance within the values shown?0ΩGo to Step 9Go to Step 8
81. Inspect the automatic transaxle wiring harness
for an intermittent short to ground or open con-
dition.
2. Inspect the automatic TFT sensor wiring har-
ness for an intermittent short to ground or open
condition.
3. Repair the circuits if necessary.
Is the repair complete?–System OK–

5A1 – 238IZF 4 HP 16 AUTOMATIC TRANSAXLE
DAEWOO V–121 BL4
Transaxle Fluid Temperature (TFT) Sensor
The TFT sensor is a positive temperature coefficient
thermistor (temperature sensitive resistor) that provides
information to the TCM regarding transaxle fluid tempera-
ture. The temperature sensor is located in valve body. Cal-
culated temperature is a factor used to determine the shift
time and shift delay time.
The internal electrical resistance of the sensor varies in
relation to the operating temperature of the transaxle fluid
(see chart).
The TCM sends a 5 volt–reference signal to the tempera-
ture sensor and measures the voltage rise in the electrical
circuit. A higher fluid temperature creates a higher resist-
ance in the temperature sensor, thereby measuring a low-
er voltage signal.
The TCM measures this voltage as another input to help
control line pressure, shift schedules and TCC apply.
When transaxle fluid temperature reaches 140°C (284°F)
the TCM enters ”hot mode.” Above this temperature the
TCM modifies transaxle shift schedules and TCC apply in
an attempt to reduce fluid temperature by reducing trans-
axle heat generation. During hot mode the TCM applies
the TCC at all times in fourth gear.
Also, the TCM commands the 2–3 and 3–4 shifts earlier
to help reduce fluid heat generation. Hot mode may not be
available on some applications.
Transaxle Sensor – Temperature To
Resistance To Voltage (approximate)
°C (°F)R high (ohms)R low (ohms)°C (°F)R high (ohms)R low (ohms)
–40 (–40)58655650 (122)1,2061,173
–30 (–22)64161160 (146)1,2951,256
–20 (–4)69967070 (158)1,3881,341
–10 (14)76073280 (176)1,4851,430
0 (32)82579990 (194)1,5851,522
10 (50)893868100 (212)1,6901,617
20 (68)963942110 (230)1,7981,715
25 (77)1,000980120 (248)1,9101,816
30 (86)1,0391,017130 (266)2,0251,920
140 (284)2,1452,027
Transaxle Electrical Connector
The transaxle electrical connector is a very important part
of the transaxle operating system. Any interference with
the electrical connection can cause the transaxle to set
Diagnostic Trouble Codes (DTCs) and/or affect proper op-
eration.
The following items can affect the electrical connections:S Bent pins in the connector from rough handling dur-
ing connection and disconnection.
S Wires backing away from the pins or coming un-
clamped (in either internal or external wiring har-
ness).
S Dirt contamination entering the connector when dis-
connected.
S Pins in the internal wiring connector backing out of
the connector or pushed out during reconnection.