2004 DAEWOO LACETTI Resistance vs temperature

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 – 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.

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 – 446IENGINE CONTROLS
DAEWOO V–121 BL4
DTC P0317 – Rough Road Sensor Source Not Detected
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Was the check complete?–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, with the engine OFF.
3. Request Diagnostic Trouble Codes (DTCs)
Are DTCs P1380, P1381, P1391, P1392 or P1393
set?–Go to
Applicable DTCGo to Step 3
3Is the vehicle equipped with the Anti–lock Brake
System (ABS)?–Go to Step 8Go to Step 4
41. Disconnect the gravity sensing rough road (G)
sensor connector.
2. Disconnect the Engine control Module (ECM)
connector.
3. Measure resistance between terminal B of the
G sensor and terminal K21 of the ECM.
Is the resistance within the specified value?0 ΩGo to Step 6Go to Step 5
5Repair open circuit.
Is the repair complete?–Go to Step 11Go to Step 6
61. Reconnect the ECM and G sensor connectors.
2. Turn the ignition ON.
3. Probe the voltage at terminal B of G sensor.
Is the voltage within the specified value?2.35–2.65 VGo to Step 10Go to Step 7
71. Turn the ignition OFF.
2. Replace the G sensor.
Is the repair complete?–Go to Step 11–
81. Turn the ignition OFF.
2. Disconnect the Electronic Brake Control Mod-
ule EBCM) connector and the ECM connector.
3. Measure the resistance between terminal 25 of
the EBCM and terminal K7 of the ECM.
Is the resistance within the specified value?0 ΩGo to Step 10Go to Step 9
9Repair open circuit.
Is the repair complete?–Go to Step 11Go to Step 10
101. Turn the ignition OFF.
2. Replace the ECM.
Is the repair complete?–Go to Step 11–
111. Using the scan tool, clear the DTCs.
2. Start the engine and idle at normal operating
temperature.
3. Operate the vehicle within the conditions for
setting this DTC as supported in the text.
Does the scan tool indicate that this diagnostic ran
and passed?–Go to Step 12Go to Step 2
12Check if any additional DTCs are set.
Are any DTCs displayed that have not been diag-
nosed?–Go to
Applicable DTC
tableSystem OK

1F – 514IENGINE CONTROLS
DAEWOO V–121 BL4
DTC P0562 – System Voltage Too Low (Engine Side)
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”
2S Install a scan tool to the Data Link Connector
(DLC) and clear the Diagnostic Trouble Codes
(DTCs).
S Start the engine and raise the engine speed
over 1400 rpm.
S Load the electrical system by turning on the
headlamps, high blower motor, etc.
Is the ignition voltage less than the specified value10 VGo to Step 3Go to Step 8
3S With the engine still running at 1400 rpm.
S Using a voltmeter measure the battery voltage
at the battery.
Is the battery voltage greater than the specified val-
ue?12 VGo to Step 4Go to
”Diagnostic
Aids”
41. Turn the ignition OFF.
2. Disconnect the Engine Control Module (ECM)
connector at the ECM.
3. Turn the ignition ON.
4. Using a voltmeter, measure the voltage at the
ignition feed circuit, terminal K18.
Is the ignition voltage greater than the specified val-
ue?10 VGo to Step 5Go to Step 6
5Check for a malfunctioning connector at the ECM
harness terminals and repair as needed.
Is the repair complete?–Go to Step 8Go to Step 7
6Repair the poor connection (high resistance) in the
ignition feed circuit.
Is the repair complete?–Go to Step 8–
71. Turn the ignition OFF.
2. Replace the ECM.
Is the repair 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
Applicable DTC
tableSystem OK

1F – 526IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1111
INTAKE AIR TEMPERATURE INTERMITTENT HIGH
VOLTAGE
Circuit Description
The Intake Air Temperature (IAT) sensor is a thermistor
which measures the temperature of the air entering the en-
gine. The Engine Control Module (ECM) applies 5 volts
through a pull–up resistor to the IAT sensor. When the in-
take air is cold, the resistance is high, and the ECM will
monitor a high signal voltage on the IAT signal circuit. If the
intake air is warm, the sensor resistance is lower causing
the ECM to monitor a lower voltage. Diagnostic Trouble
Code (DTC) P1111 will set when the ECM detects an inter-
mittent high signal voltage in the intake air temperature
sensor signal circuit or sensor.
Conditions for Setting the DTC
S IAT is less than –38°C (–36°F).
S DTCs P0502, P0117, P0118 are not set
S Engine has been running for over 120 seconds.
S Vehicles speed is less than 25 km/h (16 mph).
S Calculated air flow is less than 15 g/second.
S Engine Coolant Temperature (ECT) is above 70°C
(158°F).
Action Taken When the DTC Sets
S The ECM will substitute a default value for IAT.
S The ECM will store conditions which were present
when the DTC set as Failure Records data only.
This information will not be stored as Freeze Frame
data.
S The Malfunction Indicator Lamp (MIL) will not illumi-
nate.S A history DTC is stored.
Conditions for Clearing the MIL/DTC
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
Check for the following conditions:
S Poor connection at the ECM. Inspect harness con-
nectors for backed–out terminals, improper mating,
broken locks, improperly formed or damaged termi-
nals, and poor terminal–to–wire connection.
S Damaged harness. Inspect the wiring harness for
damage. If the harness appears to be OK, observe
the IAT display on the scan tool while moving con-
nectors and wiring harnesses related to the IAT
sensor. A change in the IAT display will indicate the
location of the fault.
S Reviewing the Fail Records vehicle mileage since
the diagnostic test last failed may help determine
how often the condition that caused the DTC to be
set occurs. This may assist in diagnosing the condi-
tion.
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.

ENGINE CONTROLS 1F – 527
DAEWOO V–121 BL4
Intake Air Temperature Sensor (Temperature Vs. Resistance Value)
°C°FOHMS°C°FOHMS
10021217715594450
801763325417280
60140667–52312300
4511 31188–15521450
35951802–30–2252700
25772796–40–40100700
Above resistance is approximate value
DTC P1111 – Intake Air Temperature Intermittent 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.
3. Request engine Diagnostic Trouble Code
(DTC).
Is DTC P0113 set?–Go to
applicable DTC
tableGo to Step 3
3Is DTC P1115 also set.–Go to Step 7Go to Step 4
4Check for a poor sensor ground circuit terminal 1 at
the Intake Air Temperature (IAT) sensor and repair
as needed.
Is the repair complete?–Go to Step 9Go to Step 5
5Check for a poor sensor signal circuit between termi-
nal 2 of the IAT sensor and terminal M7 of the Engine
Control Module (ECM) for an intermittent open and
repair as needed.
Is the repair complete?–Go to Step 9Go to Step 6
6Check for sensor signal circuit between terminal 2 of
the IAT sensor and terminal M7 of the ECM for an
intermittent short to voltage and repair as needed.
Is the repair complete?–Go to Step 9Go to Step 7
7Check for poor sensor ground circuit terminal M64
at the ECM and repair as needed.
Is the repair complete?–Go to Step 9Go to Step 8
8Check for an intermittent open or a faulty splice in the
sensor ground circuit and repair as needed.
Is the repair complete?–Go to Step 10Go to
”Diagnostic
Aids”

ENGINE CONTROLS 1F – 529
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P1112
INTAKE AIR TEMPERATURE INTERMITTENT LOW
VOLTAGE
Circuit Description
The Intake Air Temperature (IAT) sensor is a thermistor
which measures the temperature of the air entering the en-
gine. The Engine Control Module (ECM) applies 5 volts
through a pull–up resistor to the IAT sensor. When the in-
take air is cold, the resistance is high, and the ECM will
monitor a high signal voltage on the IAT signal circuit. If the
intake air is warm, the sensor resistance is lower causing
the ECM to monitor a lower voltage. Diagnostic Trouble
Code (DTC) P1111 will set when the ECM detects an inter-
mittent high signal voltage in the intake air temperature
sensor signal circuit or sensor.
Conditions for Setting the DTC
S IAT is greater than 149°C (300°F).
S DTC P0502 is not set
S Engine has been running for over two minutes.
S Vehicles speed is greater than 50 km/h (31 mph).
Action Taken When the DTC Sets
S The ECM will substitute a default value for IAT.
S The ECM will store conditions which were present
when the DTC set as Failure Records data only.
This information will not be stored as Freeze Frame
data.
S The Malfunction Indicator Lamp (MIL) will not illumi-
nate.
S A history DTC is stored.
Conditions for Clearing the MIL/DTC
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
Check for the following conditions:
S Poor connection at the ECM. Inspect harness con-
nectors for backed–out terminals, improper mating,
broken locks, improperly formed or damaged termi-
nals, and poor terminal–to–wire connection.
S Damaged harness. Inspect the wiring harness for
damage. If the harness appears to be OK, observe
the IAT display on the scan tool while moving con-
nectors and wiring harnesses related to the IAT
sensor. A change in the IAT display will indicate the
location of the fault.
S Reviewing the Fail Records vehicle mileage since
the diagnostic test last failed may help determine
how often the condition that caused the DTC to be
set occurs. This may assist in diagnosing the condi-
tion.
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 Chart.
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.