engine controls DAEWOO LACETTI 2004 Service Repair Manual

ENGINE CONTROLS 1F – 121
DAEWOO V–121 BL4
DTC P0112 – Intake Air 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 IAT sensor reading
within the value specified?15~80°CGo to
”Diagnostic
Aids”Go to Step 3
31. Turn the ignition switch to LOCK.
2. Disconnect the IAT sensor connector.
3. Turn the ignition switch to ON.
Does the scan tool show the IAT sensor reading
within the value specified? –30°CGo to Step 4Go to Step 5
4Check for a faulty connector or terminals at the IAT
sensor connector.
Is the problem found?–Go to Step 7Go to Step 6
5Check for wire for a short to ground between the IAT
connector terminal 1 and the ECM connector termi-
nal 78.
Is the problem found?–Go to Step 7Go to Step 6
6Check for wire for a short to ECM reference voltage
between the IAT sensor connector terminal 2 and
the ECM connector terminal 13.
Is the problem found?4.5 – 5.5VGo to Step 7Go to Step 9
71. Turn the ignition switch to LOCK.
2. Repair the wire or the connector terminal 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–
81. Turn the ignition switch to LOCK.
2. Replace the IAT sensor.
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–
91. Turn the ignition switch to LOCK.
2. Replace the engine control module(ECM).
3. Run the engine until it reaches operating tem-
perature.
4. Perform the diagnostic system check.
Is the repair complete?–Go to Step 10–
10Check if any additional DTCs are set.
Are any DTCs displaced that have not been diag-
nosed?–Go to the appli-
cable DTC
tableSystem OK

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 – 123
DAEWOO V–121 BL4
DTC P0113 – Intake Air 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 unit it reaches operating tem-
perature.
Does the scan tool show the intake air temperature
(IAT) sensor reading within the value specified?15~80°C
(10~176°F)Go to
”Diagnostic
Aids”Go to Step 3
31. Turn the ignition switch to LOCK.
2. Disconnect the IAT sensor connector.
3. Jumper to IAT sensor connector terminals.
4. Turn the ignition switch to ON.
Does the scan tool show the IAT sensor reading the
value specified?180°C
(356°F)Go to Step 4Go to Step 5
4Check for a faulty connector or terminals 1 and 2 of
the IAT sensor connector.
Is the problem found?–Go to Step 10Go to Step 9
5Measure the voltage between terminals 1 and 2 of
IAT sensor connector.
Does the voltage measure within the value speci-
fied?4.5~5.5VGo to Step 11Go to Step 6
6Measure the voltage between the IAT sensor con-
nector terminal 2 and the battery ground(negative)
post.
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. Check for an open or short to battery voltage in
the wire between the IAT sensor connector ter-
minal 2 and the engine control module(ECM)
connector terminal 13.
Is the problem found?–Go to Step 10Go to Step 11
81. Turn the ignition switch to LOCK.
2. Check for an open or short to battery voltage in
the wire between the IAT sensor connector ter-
minal 1 and the ECM connector terminal 78.
Is the problem found?–Go to Step 10Go to Step 11
91. Turn the ignition switch to LOCK.
2. Replace the IAT sensor.
3. Clear any DTCs from the ECM.
4. Perform the diagnostic system check.
Is the repair complete?–System OK–
101. Turn the ignition switch to LOCK.
2. Repair the wire of the connector terminals as
needed.
3. Clear any DTCs from the ECM.
4. Perform the diagnostic system check.
Is the repair complete?–System OK–

1F – 124IENGINE CONTROLS
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
111. Replace the ECM.
2. Perform the diagnostic system check.
Is the repair complete?–Go to Step 12–
12Check if any additional DTCs are set.
Are any DTCs displaced that have not been diag-
nosed?–Go to
applicable
DTC tableSystem OK

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–

ENGINE CONTROLS 1F – 127
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
91. Replace the ECM.
2. Run the engine until it reaches operating tem-
perature.
3. Perform the diagnostic system check.
Is the repair complete?–Go to Step 10–
10Check if any additional DTCs are set.
Are any DTCs displaced that have not been diag-
nosed?–Go to applica-
ble DTC tableSystem 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–

1F – 130IENGINE CONTROLS
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
91. Replace the ECM.
2. Run the engine until it reaches operating tem-
perature.
3. Perform the diagnostic system check.
Is the repair complete?–Go to Step 10–
10Check if any additional DTCs are set.
Are any DTCs displaced that have not been diag-
nosed?–Go to applica-
ble DTC tableSystem OK