2004 DAEWOO LACETTI ignition

1F – 356IENGINE CONTROLS
DAEWOO V–121 BL4
DTC P0112 – Intake Air Temperature Low Voltage
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Was the check performed?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Install a scan tool to the Data Link Connector
(DLC).
2. Turn the ignition ON.
Is the Intake Air Temperature (IAT) value greater
than the specified value?128°C
(262 °F)Go to Step 4Go to Step 3
31. Turn the ignition switch ON with the engine
OFF, review Freeze Frame data, and note the
parameters.
2. Operate the vehicle within the Freeze Frame
conditions and Conditions for Setting The DTC
as noted.
Is the IAT sensor value greater than the specified
value?128°C
(262 °F)Go to Step 4Go to
”Diagnostic
Aids”
41. Turn the ignition switch OFF.
2. Disconnect the IAT sensor electrical connector.
3. Turn the ignition switch ON.
Is the IAT sensor value below the specified value?–30 °C
(–22 °F)Go to Step 5Go to Step 6
5Replace IAT sensor.
Is the repair complete?–Go to Step 10–
6With a test light connected to battery +, probe the
IAT sensor signal circuit, terminal 2 at the IAT sensor
connector.
Does the test light illuminate?–Go to Step 7Go to Step 9
71. Turn the ignition switch OFF.
2. Disconnect the Engine Control Module (ECM)
connector.
3. With a test light connected to B+, probe the
IAT sensor signal circuit, terminal 2 at the IAT
sensor electrical connector.
Does the test light illuminate?–Go to Step 8Go to Step 9
8Repair the short to ground circuit in the IAT sensor
signal circuit as needed.
Is the repair complete?–Go to Step 10–
91. Turn the ignition OFF.
2. Replace the ECM.
Is the action complete?–Go to Step 10–

1F – 358IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0113
INTAKE AIR TEMPERATURE HIGH VOLTAGE
Circuit Description
The Intake Air Temperature (IAT) sensor uses a thermistor
to control the signal voltage to the Engine Control Module
(ECM). The ECM supplies a 5 volt reference and a ground
to the sensor. When the air is cold, the resistance is high;
therefore the IAT signal voltage will be high. If the intake
air is warm, resistance is low; therefore the IAT signal volt-
age will be low.
Conditions for Setting the DTC
S IAT is less than –38°C (–36°F).
S Vehicles speed is less than 25 km/h (16 mph).
S Engine run time is greater than 120 seconds.
S Engine Coolant Temperature (ECT) is above 70 °C
158 °F).
S Calculated air are flow is less than 15 g/second.
S DTC P0502, P0117, P0118 not set.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will illuminate
after three consecutive ignition cycle with a fail.
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 ECM will substitute a default value for intake
air temperature. 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
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. Re-
fer to ”Temperature vs. Resistance” in this section.
Test Description
Number(s) below refer to the step number(s) on the Diag-
nostic Table.
1. The On–Board Diagnostic (EOBD) System Check
prompts the technician to complete some basic
checks and store the freeze frame and failure re-
cords data on the scan tool if applicable. This
creates an electronic copy of the data taken when
the malfunction occurred. The information is then
stored on the scan tool for later reference.
4. This step simulates a DTC P0112. If the ECM
senses the change, the ECM and wiring are OK.
5. This step will determine if the reason the ECM did
not sense the change was due to a open ground or
signal circuit or malfunctioning ECM.
11. The replacement ECM must be reprogrammed.
Refer to the latest Techline procedure for ECM re-
programming.

ENGINE CONTROLS 1F – 359
DAEWOO V–121 BL4
DTC P0113 Intake Air Temperature High Voltage
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Was the check performed?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Install a scan tool to the Data Link Connector
(DLC).
2. Turn the ignition ON.
Is the Intake Air Temperature (IAT) value less than
the specified value?–30 °C
(–22 °F)Go to Step 4Go to Step 3
31. Turn the ignition switch ON with the engine
OFF, review Freeze Frame data, and note the
parameters.
2. Operate the vehicle within the Freeze Frame
conditions and Conditions for Setting The DTC
as noted.
Is the IAT sensor value less than the specified val-
ue?–30 °C
(–22 °F)Go to Step 4Go to
”Diagnostic
Aids”
41. Turn the ignition switch OFF.
2. Disconnect the IAT sensor electrical connector.
3. Turn the ignition switch ON.
4. Jumper the IAT sensor signal circuit terminal 2
and ground circuit terminal 1.
Is the IAT sensor value greater than the specified
value?130 °C
(266 °F)Go to Step 6Go to Step 5
5Jumper the IAT sensor signal circuit at terminal 1 to
ground.
Is the IAT sensor value greater than the specified
value?130 °C
(266 °F)Go to Step 7Go to Step 8
6Check for a poor connection at the IAT sensor con-
nector and repair or replace any malfunctioning ter-
minal as needed.
Is the repair necessary?–Go to Step 12Go to Step 10
7Check the IAT sensor ground circuit for an open and
repair as needed.
Is the repair complete?–Go to Step 12Go to Step 9
8Check the IAT sensor signal circuit for an open and
repair as needed.
Is the repair complete?–Go to Step 12Go to Step 9
9Check for a poor IAT sensor ground circuit at termi-
nal M64 or a poor IAT sensor signal circuit terminal
M7 connection at Engine Control Module (ECM) and
repair as needed.
Is the repair necessary?–Go to Step 12Go to Step 11
10Replace the IAT sensor.
Is the action complete?–Go to Step 12
111. Turn the ignition OFF.
2. Replace the ECM.
Is the action complete?–Go to Step 12–

ENGINE CONTROLS 1F – 361
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0117
ENGINE COOLANT TEMPERATURE LOW VOLTAGE
Circuit Description
The Engine Coolant Temperature (ECT) sensor uses a
thermistor to control the signal voltage to the Engine Con-
trol Module (ECM). The ECM supplies a 5 volt reference
and a ground to the sensor. When the engine coolant is
cold, the resistance is high; therefore the ECT signal volt-
age will be high. If the engine coolant is warm, sensor re-
sistance becomes less; therefore the IAT signal voltage
drops. At normal engine operating temperature, the volt-
age will be between 1.5 to 2.0 volts at the ECT signal termi-
nal.
The ECT sensor is used to control following items:
S Fuel delivery.
S Ignition.
S Evaporative (EVAP) Emission canister purge valve.
S Idle Air Control (IAC) valve.
S Electric cooling fan.
Conditions for Setting the DTC
S Engine run time is greater than 60 seconds.
S ECT is less tan 149°C (300°F)
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 Both cooling fans turns on.
S The ECM will default to 20°C (68°F) for engine
coolant temperature for the first 60 seconds of en-
gine run time and then 92°C (198°F). 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 engine start the ECT should rise steadily to 90°C
(194°F) then stabilize when the thermostat opens.
Use the Temperature vs. Resistance Values table to eval-
uate the possibility of a skewed sensor. Refer to”Tempera-
ture vs. Resistance” in this section.
Test Description
Number(s) below refer to the step number(s) on the Diag-
nostic Table.
1. The On–Board Diagnostic (EOBD) System Check
prompts the technician to complete some basic
checks and store the freeze frame and failure re-
cords data on the scan tool if applicable. This
creates an electronic copy of the data taken when
the malfunction occurred. The information is then
stored on the scan tool for later reference.
4. This step simulates a DTC P0118 condition. If the
ECM senses the change, then the ECM and the
ECT wiring are OK.
7. The replacement ECM must be reprogrammed.
Refer to the latest Techline procedure for ECM re-
programming.

1F – 362IENGINE CONTROLS
DAEWOO V–121 BL4
DTC P0117 – Engine Coolant Temperature Low Voltage
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Was the check performed?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Install a scan tool to the Data Link Connector
(DLC).
2. Turn the ignition ON.
Is the Engine Coolant Temperature (ECT) sensor
value greater than the specified value?130 °C
(266 °F)Go to Step 4Go to Step 3
31. Turn the ignition switch ON with the engine
OFF, review Freeze Frame data, and note the
parameters.
2. Operate the vehicle within the Freeze Frame
conditions and Conditions for Setting The DTC
as noted.
Is the ECT sensor value greater than the specified
value?130 °C
(266 °F)Go to Step 4Go to
”Diagnostic
Aids”
41. Turn the ignition switch OFF.
2. Disconnect the ECT sensor connector.
3. Turn the ignition switch ON.
Is the ECT sensor value below the specified value?–30 °C
(–22 °F)Go to Step 6Go to Step 5
5Check the ECT sensor signal circuit at terminal 1 for
a short to ground and repair as needed.
Is the repair complete?–Go to Step 8Go to Step 7
6Replace ECT sensor.
Is the repair complete?–Go to Step 8–
71. Turn the ignition OFF.
2. Replace the Engine Control Module (ECM).
Is the action complete?–Go to Step 8–
81. Using the scan tool, clear the Diagnostic
Trouble Codes (DTCs).
2. Start the engine and idle at normal operating
temperature.
3. Operate the vehicle within the Conditions for
setting this DTC as specified in the supporting
text.
Does the scan tool indicate that this diagnostic has
run and passed?–Go to Step 9Go to Step 2
9Check if any additional DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to applica-
ble DTC tableSystem OK

ENGINE CONTROLS 1F – 363
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0118
ENGINE COOLANT TEMPERATURE HIGH VOLTAGE
Circuit Description
The Engine Coolant Temperature (ECT) sensor uses a
thermistor to control the signal voltage to the Engine Con-
trol Module (ECM). The ECM supplies a 5 volt reference
and a ground to the sensor. When the engine coolant is
cold, the resistance is high; therefore the ECT signal volt-
age will be high. If the engine coolant is warm, sensor re-
sistance becomes less; therefore the IAT signal voltage
drops. At normal engine operating temperature, the volt-
age will be between 1.5 to 2.0 volts at the ECT signal termi-
nal.
The ECT sensor is used to control following items:
S Fuel delivery.
S Ignition.
S Evaporative Emission (EVAP) canister purge valve.
S Idle Air Control (IAC) valve.
S Electric cooling fan.
Conditions for Setting the DTC
S ECT is less than –38°C (–36°F).
S Engine run time is greater than 90 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 Both cooling fans turns on.
S The ECM will default to 20 °C (68 °F) for engine
coolant temperature for the first 60 seconds of en-
gine run time and then 92 °C (198 °F). 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
Normal operating temperature for the engine cooling sys-
tem is between 90°C(194°F) and 95°C(203°F).
Use the Temperature vs. Resistance Values table to eval-
uate the possibility of a skewed sensor. Refer to”Tempera-
ture vs. Resistance” in this section.
Test Description
Number(s) below refer to the step number(s) on the Diag-
nostic Table.
1. The On–Board Diagnostic (EOBD) System Check
prompts the technician to complete some basic
checks and store the freeze frame and failure re-
cords data on the scan tool if applicable. This
creates an electronic copy of the data taken when
the malfunction occurred. The information is then
stored on the scan tool for later reference.
4. This step simulates a DTC P0117 condition. If the
ECM senses the change, then the ECM and the
ECT wiring are OK.
11. The replacement ECM must be reprogrammed.
Refer to the latest Techline procedure for ECM re-
programming.

1F – 364IENGINE CONTROLS
DAEWOO V–121 BL4
DTC P0118 – Engine Coolant Temperature High Voltage
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Was the check performed?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
21. Install a scan tool to the Data Link Connector
(DLC).
2. Turn the ignition ON.
Is the engine Coolant Temperature (ECT) value less
than the specified value?–30 °C
(–22 °F)Go to Step 4Go to Step 3
31. Turn the ignition switch ON with the engine
OFF, review Freeze Frame data, and note the
parameters.
2. Operate the vehicle within the Freeze Frame
conditions and Conditions for Setting The DTC
as noted.
Is the ECT sensor value less than the specified val-
ue?–30 °C
(–22 °F)Go to Step 4Go to
”Diagnostic
Aids”
41. Turn the ignition switch OFF.
2. Disconnect the ECT sensor connector.
3. Turn the ignition switch ON.
4. Jumper the ECT sensor signal circuit terminal
1 and ground circuit terminal 2.
Is the ECT sensor value greater than the specified
value?130 °C
(266 °F)Go to Step 6Go to Step 5
5Jumper the ECT sensor signal circuit at terminal 1
to ground.
Is the ECT sensor value greater than the specified
value?130 °C
(266 °F)Go to Step 7Go to Step 8
6Check for a poor connection at the ECT sensor con-
nector and repair or replace any malfunctioning ter-
minal as needed.
Is the repair complete?–Go to Step 12Go to Step 10
7Check the ECT sensor ground circuit for an open
and repair as needed.
Is the repair complete?–Go to Step 12Go to Step 9
8Check the ECT sensor signal circuit for an open and
repair as needed.
Is the repair complete?–Go to Step 12Go to Step 9
9Check for a poor ECT sensor ground circuit at termi-
nal M64 or a poor ECT sensor signal circuit terminal
M28 connection at Engine Control Module (ECM)
and repair as needed.
Is the repair complete?–Go to Step 12Go to Step 11
10Replace the ECT sensor.
Is the repair complete?–Go to Step 12–
111. Turn the ignition OFF.
2. Replace the ECM.
Is the action complete?–Go to Step 12–

1F – 366IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0122
THROTTLE POSITION SENSOR LOW VOLTAGE
Circuit Description
The Engine Control Module (ECM) supplies a 5 volt refer-
ence voltage signal and a ground to the Throttle Position
(TP) sensor. The TP sensor sends a voltage signal back
to the ECM relative to the throttle plate opening. The volt-
age signal will vary from approximately 0.33 volts at closed
throttle, to over 4.3 volts at Wide Open Throttle (WOT).
The TP signal is used by the ECM for fuel control and for
most of the ECM controlled outputs. The TP signal is one
of the most important inputs used by the ECM for fuel con-
trol and most of the ECM controlled outputs.
Conditions for Setting the DTC
S TP sensor voltage indicates a throttle voltage less
than 0.14 volts.
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 TP angle will default to 0% when the vehicle
speed is less than 3 km/h (2 mph) and 10% when
the vehicle speed is greater than 3 km/h (2 mph).
The scan tool will not display the default 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 a scan
tool information data to determine the status of the DTC.
If the dc occurs intermittently, using the Diagnostic table
may help isolate the problem.
Test Description
Number(s) below refer to the step number(s) on the Diag-
nostic Table.
1. The On–Board Diagnostic (EOBD) System Check
prompts the technician to complete some basic
checks and store the freeze frame and failure re-
cords data on the scan tool if applicable. This
creates an electronic copy of the data taken when
the malfunction occurred. The information is then
stored on the scan tool for later reference.
2. The TP sensor has an auto zeroing feature. If the
voltage reading is between 0.2 to 0.9 volts, the
ECM will assume the TP sensor is at a closed
throttle position (0%).
5. Simulates a high voltage signal which will identify
an open in the signal circuit.
6. If additional DTCs are set, check the 5v reference
circuits for a short to ground.
8. If the test light illuminates while probing the TP sig-
nal circuit, then the TP signal circuit is shorted to
ground.
11. The replacement ECM must be reprogrammed.
Refer to the latest Techline procedure for ECM re-
programming.