engine coolant DAEWOO LACETTI 2004 Service Manual PDF

1F – 120IENGINE CONTROLS
DAEWOO V–121 BL4
J3B11F51
BRNORN
/BLK
DIAGNOSTIC TROUBLE CODE (DTC) P0112
INTAKE AIR TEMPERATURE SENSOR LOW VOLTAGE
Circuit Description
The Intake Air Temperature (IAT) Sensor uses a thermis-
tor to control the signal voltage to the engine control mod-
ule (ECM). The ECM supplies a 5 volt reference voltage
and a ground to the sensor. When the air is cold, the resist-
ance is high ; therefore IAT sensor signal voltage will be
high. If the intake air is warm, resistance is low ; therefore
the IAT sensor signal voltage will be low.
Conditions for Setting the DTC
S IAT voltage is less than 0.01V.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will illuminate
after three consecutive trip with a fail.
S The ECM will record operating conditions at the
time the diagnostic fail. This information will be
stored in the Freeze Frame and Failure Records
buffers.
S A history DTC is stored.S The ECM will default to 605C(1405F) for intake air
temperature. The scan tool will not show the de-
faulted value.
Conditions for Clearing the MIL/DTC
S The MIL will turn off after four consecutive ignition
cycles in which the diagnostic runs without a fault.
S A history DTC will clear after 40 consecutive warm
up cycles without a fault.
S DTC(s) can be cleared by using the scan tool.
S Disconnecting the ECM battery feed for 10 sec-
onds.
Diagnostic Aids
If the vehicle is at ambient temperature, compare the IAT
sensor to the engine coolant temperature(ECT) sensor.
The IAT sensor and the ECT sensor should be relatively
close to each other. Use the temperature vs. Resistance
Values table to evaluate the possibility of a skewed sensor.
Refer to ”Temperature vs. Resistance” in this section.

1F – 122IENGINE CONTROLS
DAEWOO V–121 BL4
J3B11F51
BRNORN
/BLK
DIAGNOSTIC TROUBLE CODE (DTC) P0113
INTAKE AIR TEMPERATURE SENSOR HIGH VOLTAGE
Circuit Description
The Intake Air Temperature (IAT) Sensor uses a thermis-
tor to control the signal voltage to the engine control mod-
ule (ECM). The ECM supplies a 5 volt reference voltage
and a ground to the sensor . when the air is cold, the resist-
ance is high ; therefore IAT sensor signal voltage will be
high. If the intake air is warm, resistance is low ; therefore
the IAT sensor signal voltage will be low.
Conditions for Setting the DTC
S IAT voltage is less than 4.99V.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will illuminate
after three consecutive trip with a fail.
S The ECM will record operating conditions at the
time the diagnostic fail. This information will be
stored in the Freeze Frame and Failure Records
buffers.
S A history DTC is stored.S The ECM will default to 605C(1405F) for intake air
temperature. The scan tool will not show the de-
faulted value.
Conditions for Clearing the MIL/DTC
S The MIL will turn off after four consecutive ignition
cycles in which the diagnostic runs without a fault.
S A history DTC will clear after 40 consecutive warm
up cycles without a fault.
S DTC(s) can be cleared by using the scan tool.
S Disconnecting the ECM battery feed for 10 sec-
onds.
Diagnostic Aids
S If the vehicle is at ambient temperature, compare
the IAT sensor to the engine coolant temperature
(ECT) sensor. The IAT sensor and the ECT sensor
should be relatively close to each other.
S Use the temperature vs. Resistance Values table to
evaluate the possibility of a skewed sensor. Refer
to ”Temperature vs. Resistance” in this section.

ENGINE CONTROLS 1F – 125
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0117
ENGINE COOLANT TEMPERATURE SENSOR LOW
VOLTAGE
Circuit Description
The Engine Coolant Temperature sensor (ECT) uses a
thermistor to control the signal voltage to the engine con-
trol module (ECM).
The ECM supplies a voltage on the signal circuit to the
sensor. When the engine coolant is cold, the resistance is
high; therefore the ECT signal voltage will be high.
As the engine warms, the sensor resistance becomes
less, and the voltage drops. At normal engine operating
temperature, the voltage will be between 1.5 and 2.0 volts
at the ECT signal terminal.
The ECT sensor is used to the following items:
S Fuel delivery.
S Lock Up Clutch (LUC).
S Ignition.
S Evaporative Emission (EVAP) Canister Purge
Valve.
S Electric cooling fan.
Conditions for Setting the DTC
S ECT voltage is less than 0.03V.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will illumi-
nate.S The ECM will record operating conditions at the
time the diagnostic fails. This information will be
stored in the Freeze Frame and Failure Records
buffers.
S A history DTC is stored.
S The coolant fan turns ON.
S The ECM will default to 20°C (68°F) for the first 60
seconds of the engine run time, and then 92 °C
(198 °F).
S The scan tool will not show the defaulted value.
Conditions for Clearing the MIL/DTC
S The MIL will turn off after four consecutive ignition
cycles in which the diagnostic runs without a fault.
S A history DTC will clear after 40 consecutive warm–
up cycles without a fault.
S DTC(s) can be cleared by using the scan tool.
S Disconnecting the ECM battery feed for more than
10 seconds.
Diagnostic Aids
After the engine has started, the ECT should rise steadily
to about 90°C (194°F) then stabilize when the thermostat
opens.
Use the temperature vs. Resistance values table to evalu-
ate the possibility of a skewed sensor. Refer to ”Tempera-
ture vs. Resistance” in this section.

1F – 126IENGINE CONTROLS
DAEWOO V–121 BL4
DTC P0117 – Engine Coolant Temperature Sensor Low Voltage
StepActionValue(s)YesNo
1Perform an Euro On–Board Diagnostic (EOBD)
System Check.
Is the system check complete?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Connect the scan tool to the data link connec-
tor (DLC).
2. Run the engine until it reaches operating tem-
perature.
Does the scan tool show the ECT sensor reading
within the value specified?80~110°C
(176~260°F)Go to
”Diagnostic
Aids”Go to Step 3
31. Turn the ignition switch to LOCK.
2. Disconnect the ECT sensor connector.
3. Turn the ignition switch to ON.
Does the scan tool show the IAT sensor reading
within the value specified?–30°C
(–22°F)Go to Step 4Go to Step 6
41. Jumper the ECT sensor signal circuits at termi-
nal 1 and 2.
2. Turn the ignition switch to ON.
Does the scan tool show the ECT sensor reading
within the value specified?120°CGo to Step 5Go to Step 6
51. Replace the ECT sensor.
2. Clear any DTCs from the ECM.
3. Perform the diagnostic system check.
Is the replacement complete?–System OK–
6Measure the voltage between ECT terminal 2 and
ground.
Does the voltage measure within the value speci-
fied?4.5–5.5VGo to Step 7Go to Step 8
71. Turn the ignition switch to LOCK.
2. Disconnect the ECM wiring connector.
3. Check for a faulty connector or terminals at the
ECT sensor connectors and ECM connectors
for short to ECM reference voltage.
Is the problem found?–Go to Step 9Go to Step 8
81. Turn the ignition switch to LOCK.
2. Repair the wire of the connector terminals as
needed.
3. Clear any DTCs from the ECM.
4. Run the engine until it reaches operating tem-
perature.
5. Perform the diagnostic system check.
Is the repair complete?–System OK–

1F – 128IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0118
ENGINE COOLANT TEMPERATURE SENSOR HIGH
VOLTAGE
Circuit Description
The coolant temperature sensor (ECT) uses a thermistor
to control the signal voltage to the engine control module
(ECM).
he ECM supplies a voltage on the signal circuit to the sen-
sor. When the air is cold, the resistance is high; therefore
the ECT sensor signal voltage will be high.
As the engine warms, the sensor resistance becomes
less, and the voltage drops. At normal engine operating
temperature, the voltage will be between 1.5 and 2.0 volts
at the ECT sensor signal terminal.
The ECT sensor is used to the following items:
S Fuel delivery.
S Lock Up Clutch (LUC).
S Ignition.
S Evaporative Emission (EVAP) Canister Purge
Valve.
S Electric cooling fan.
Conditions for Setting the DTC
S ECT voltage is greater than 4.98V.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will illumi-
nate.S The ECM will record operating conditions at the
time the diagnostic fails. This information will be
stored in the Freeze Frame and Failure Records
buffers.
S A history DTC is stored.
S The coolant fan turns ON.
S The ECM will substitutes a fixed MAP value and
use TP to control the fuel delivery (the scan tool will
not show defaulted)
Conditions for Clearing the MIL/DTC
S The MIL will turn off after four consecutive ignition
cycles in which the diagnostic runs without a fault.
S A history DTC will clear after 40 consecutive warm–
up cycles without a fault.
S DTC(s) can be cleared by using the scan tool.
S Disconnecting the ECM battery feed for more than
10 seconds.
Diagnostic Aids
After the engine has started, the ECT should rise steadily
to about 90°C (194°F) then stabilize when the thermostat
opens.
Use the temperature vs. Resistance values table to evalu-
ate the possibility of a skewed sensor. Refer to ”Tempera-
ture vs. Resistance” in this section.

ENGINE CONTROLS 1F – 129
DAEWOO V–121 BL4
DTC P0118 – Engine Coolant Temperature Sensor High Voltage
StepActionValue(s)YesNo
1Perform an Euro On–Board Diagnostic (EOBD)
System Check.
Is the system check complete?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Connect the scan tool to the data link connec-
tor (DLC).
2. Run the engine until it reaches operating tem-
perature.
Does the scan tool show the ECT sensor reading
within the value specified?80~110°C
(176~260°F)Go to
”Diagnostic
Aids”Go to Step 3
31. Turn the ignition switch to LOCK.
2. Disconnect the ECT sensor connector.
3. Turn the ignition switch to ON.
Does the scan tool show the ECT sensor reading
within the value specified?–30°CGo to Step 4Go to Step 6
41. Jumper the ECT sensor signal circuits at termi-
nal 1 and 2.
2. Turn the ignition switch to ON.
Does the scan tool show the ECT sensor reading
within the value specified?180°C
(356°F)Go to Step 5Go to Step 6
51. Replace the ECT sensor.
2. Clear any DTCs from the ECM.
3. Perform the diagnostic system check.
Is the replacement complete?–System OK–
6Measure the voltage between ECT terminal 1 and
ground.
Does the voltage measure within the value speci-
fied?4.5–5.5VGo to Step 7Go to Step 8
71. Turn the ignition switch to LOCK.
2. Disconnect the ECM wiring connector.
3. Check for a faulty connector or terminals at the
ECT sensor connector terminal 2 and the ECM
connector terminal 19 for an open or short to
battery voltage.
Is the problem found?–Go to Step 8Go to Step 9
81. Turn the ignition switch to LOCK.
2. Repair the wire of the connector terminals as
needed.
3. Clear any DTCs from the ECM.
4. Run the engine until it reaches operating tem-
perature.
5. Perform the diagnostic system check.
Is the repair complete?–System OK–

ENGINE CONTROLS 1F – 131
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0122
THROTTLE POSITION SENSOR LOW VOLTAGE
Circuit Description
The aim of the MTIA (Main Throttle Idle Actuator) is to con-
trol the idle speed with the throttle body itself. The throttle
is motorized for low opening angle (05, 195). The charac-
teristics of the airflow are not the same for low and high
opening angles. As a matter of fact, the gradient of the
mass air flow function of TPS is lower for small angles that
permits to be more precise during the idle speed control.
Out of idle speed the throttle is actuated mechanically by
a classical bowdencable.
The throttle position sensor (TPS) provides a voltage sig-
nal that changes in relation to the throttle plate angle. The
signal voltage will vary from about nearly 5.0 V at idles to
about 0.2V to 0.4 V at wide–open throttle. The TPS is one
of the most important inputs used by the ECM for fuel con-
trol and other functions such as idle, wide open throttle,
deceleration enleanment, and acceleration enrichment.
Conditions for Setting the DTC
S TPS voltage is less than 0.3V.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will illumi-
nate.S The ECM will record operating conditions at the
time the diagnostic fails. This information will be
stored in the Freeze Frame and Failure Records
buffers.
S A history DTC is stored.
S The coolant fan turns ON.
S The ECM will default to 20°C (68°F) for the first 60
seconds of the engine run time, and then 92 °C
(198 °F).
S The scan tool will not show the defaulted value.
Conditions for Clearing the MIL/DTC
S The MIL will turn off after four consecutive ignition
cycles in which the diagnostic runs without a fault.
S A history DTC will clear after 40 consecutive warm–
up cycles without a fault.
S DTC(s) can be cleared by using the scan tool.
S Disconnecting the ECM battery feed for more than
10 seconds.
Diagnostic Aids
If the DTC P0122 cannot be duplicated, the information in-
cluded in the Freeze Frame data can be useful. Use the
scan tool DTC information data to determine the status of
the DTC. If the DTC occurs intermittently, using the DTC
P0121 diagnostic table may help isolate the problem.

1F – 134IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0123
THROTTLE POSITION SENSOR HIGH VOLTAGE
Circuit Description
The aim of the MTIA (Main Throttle Idle Actuator) is to con-
trol the idle speed with the throttle body itself. The throttle
is motorized for low opening angle (05, 195). The charac-
teristics of the airflow are not the same for low and high
opening angles. As a matter of fact, the gradient of the
mass air flow function of TPS is lower for small angles that
permits to be more precise during the idle speed control.
Out of idle speed the throttle is actuated mechanically by
a classical bowdencable.
The throttle position sensor (TPS) provides a voltage sig-
nal that changes in relation to the throttle plate angle. The
signal voltage will vary from about nearly 5.0 V at idles to
about 0.2V to 0.4 V at wide–open throttle. The TPS is one
of the most important inputs used by the ECM for fuel con-
trol and other functions such as idle, wide open throttle,
deceleration enleanment, and acceleration enrichment.
Conditions for Setting the DTC
S TPS voltage is greater than 4.8V.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will illumi-
nate.
S The ECM will record operating conditions at the
time the diagnostic fails. This information will be
stored in the Freeze Frame and Failure Records
buffers.S A history DTC is stored.
S The coolant fan turns ON.
S The ECM will default to 20°C (68°F) for the first 60
seconds of the engine run time, and then 92 °C
(198 °F).
Conditions for Clearing the MIL/DTC
S The MIL will turn off after four consecutive ignition
cycles in which the diagnostic runs without a fault.
S A history DTC will clear after 40 consecutive warm–
up cycles without a fault.
S DTC(s) can be cleared by using the scan tool.
S Disconnecting the ECM battery feed for more than
10 seconds.
Diagnostic Aids
If the DTC P0123 cannot be duplicated, the information in-
cluded in the Freeze Frame data can be useful. Use the
scan tool DTC information data to determine the status of
the DTC. If the DTC occurs intermittently, using the DTC
P0121 diagnostic table may help isolate the problem.
With the ignition ON and the throttle at closed position the
voltage should read between 0.20 V and 0.90V and in-
crease steadily to over 4.5V at WOT.
DTCs P0123 and P0113 stored at the same time could be
the result of an open sensor ground circuit.

ENGINE CONTROLS 1F – 137
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0131
FRONT HEATED OXYGEN SENSOR LOW VOLTAGE
Circuit Description
The engine control module (ECM) supplies a voltage of
about 450mm volts between the ECM terminals 44 and 13.
The oxygen (O2) sensor varies the voltage within a range
of about 1volt if the exhaust is rich, down to about 100mm
volts if the exhaust is lean. The O2 sensor is like an open
circuit and produces no voltage when it is below
360°C(600°F). An open O2 sensor circuit or a cold O2
sensor causes ”open loop” operation.
Conditions for Setting the DTC
(Case A)
S The engine controls system is in closed loop.
S Engine speed is less than 6,000rpm.
S The oxygen sensor voltage is below 0.07V for at
least 40seconds.
S DTCs P0107, P0108, P0117, P0118, P0122,
P0123, P0335, P0336, P0341, P0342, P0400,
P0404, P0405, P0406 are NOT SET.
(Case B)
S The engine controls system is in closed loop.
S Engine speed is less than 6,000rpm.
S The oxygen sensor voltage is between 0.352 and
0.499 at least 10 seconds.Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will illumi-
nate.
S The ECM will record operating conditions at the
time the diagnostic fails. This information will be
stored in the Freeze Frame and Failure Records
buffers.
S A history DTC is stored.
S The coolant fan turns ON.
Conditions for Clearing the MIL/DTC
S The MIL will turn off after four consecutive ignition
cycles in which the diagnostic runs without a fault.
S A history DTC will clear after 40 consecutive warm–
up cycles without a fault.
S DTC(s) can be cleared by using the scan tool.
S Disconnecting the ECM battery feed for more than
10 seconds.
Diagnostic Aids
Normal scan tool voltage varies between 0.1volts and 0.9
volts while in closed loop.
Inspect the oxygen (O2) sensor wire. The O2 sensor may
be positioned incorrectly and contacting the exhaust man-
ifold.

1F – 140IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0132
FRONT HEATED OXYGEN SENSOR HIGH VOLTAGE
Circuit Description
The engine control module (ECM) supplies a voltage of
about 450mm volts between the ECM terminals 44 and 13.
The oxygen (O2) sensor varies the voltage within a range
of about 1volt if the exhaust is rich, down to about 100mm
volts if the exhaust is lean. The O2 sensor is like an open
circuit and produces no voltage when it is below
360°C(600°F). An open O2 sensor circuit or a cold O2
sensor causes ”open loop” operation.
Conditions for Setting the DTC
S The oxygen sensor voltage is more than 1.2V.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will illumi-
nate.
S The ECM will record operating conditions at the
time the diagnostic fails. This information will be
stored in the Freeze Frame and Failure Records
buffers.
S A history DTC is stored.
S The coolant fan turns ON.
Conditions for Clearing the MIL/DTCS The MIL will turn off after four consecutive ignition
cycles in which the diagnostic runs without a fault.
S A history DTC will clear after 40 consecutive warm
up cycles without a fault.
S DTC(s) can be cleared by using the scan tool.
S Disconnecting the ECM battery feed for 10 sec-
onds.
Diagnostic Aids
Normal scan tool voltage varies between 0.1volts and 0.9
volts while in closed loop.
Inspect the oxygen (O2) sensor wire. The O2 sensor may
be positioned incorrectly and contacting the exhaust man-
ifold.
Check for an intermittent ground in the wire between the
O2 sensor and the engine control module.
Perform an injector 2alance test to determine if a restricted
fuel injector may be causing the lean condition.
Vacuum of crankcase leaks will cause a lean running con-
dition.
An exhaust manifold gasket leak of a cracked exhaust
manifold may cause outside air to be pulled into the ex-
haust and past the sensor.