2004 DAEWOO LACETTI engine coolant

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 – 372IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0131
FRONT HEATED OXYGEN SENSOR (HO2S1) LOW
VOLTAGE
Circuit Description
The Engine Control Module (ECM) supplies a voltage of
about 0.45 volts between terminals M12 and M29 (if mea-
sured with a 10 megohm digital voltmeter, this may read
as low as 0.32 volts). The Front Heated Oxygen sensor 1
(HO2S1) varies the voltage within a range of about 1 volt
if the exhaust is rich, down through about 0.10 volts if the
exhaust is lean.
The sensor is like an open circuit and produces no voltage
when it is below 315°C(600°F). An open sensor circuit or
cold sensor causes Open Loop operation.
If the HO2S1 pigtail wiring, connector, or terminal is dam-
aged, the entire HO2S1 assembly must be replaced. Do
not attempt to repair the wiring, connector, or terminals. In
order for the sensor to function properly, it must have a
clean air reference provided to it. This clean air reference
is obtained by way of the HO2S1 wire(s). Any attempt to
repair the wires, connector or terminals could result in the
obstruction of the air reference and degrade the HO2S1
performance. Refer to ”Front Heated Oxygen Sensor” in
this section.Conditions for Setting the DTC
S HO2S1 voltage is less than 0.05 volts.
S Closed loop stoichiometry.
S Engine Coolant Temperature (ECT) is greater than
60°C(140°F).
S System voltage is greater than 10 volts.
S DTCs P0106, P0107, P0108, P0117, P0118,
P0122, P0123, P0171, P0172, P0201, P0202,
P0203, P0204, P0300, P0336, P0337, P0351,
P0352, P0402, P0404, P0405, P0406, P0506,
P0507, P1404, and P0443 are not set.
S 3 second delay after conditions are met.
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 vehicle will operate in Open Loop.

ENGINE CONTROLS 1F – 375
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0132
FRONT HEATED OXYGEN SENSOR (HO2S1) HIGH
VOLTAGE
Circuit Description
The Engine Control Module (ECM) supplies a voltage of
about 0.45 volts between terminals M12 and M29 (if mea-
sured with a 10 megohm digital voltmeter, this may read
as low as 0.32 volts). The Front Heated Oxygen Sensor
(HO2S1) varies the voltage within a range of about 1 volt
if the exhaust is rich, down through about 0.10 volts if the
exhaust is lean.
The sensor is like and open circuit and produces no volt-
age when it is below 315°C (600°F). An open sensor cir-
cuit or cold sensor causes Open Loop operation.
If the HO2S1 pigtail wiring, connector, or terminal is dam-
aged, the entire HO2S1 assembly must be replaced. Do
not attempt to repair the wiring, connector, or terminals. In
order for the sensor to function properly, it must have a
clean air reference provided to it. This clean air reference
is obtained by way of the HO2S1 wire(s). Any attempt to
repair the wires, connector or terminals could result in the
obstruction of the air reference and degrade the HO2S1
performance. Refer to”Front Heated Oxygen Sensor” in
this section.
Conditions for Setting the DTCS HO2S1 voltage is greater than 0.952 volts.
S Closed loop stoichiometry.
S Engine Coolant Temperature (ECT) is greater than
60°C(140°F).
S System voltage is greater than 10 volts.
S DTCs P0106, P0107, P0108, P0117, P0118,
P0122, P0123, P0171, P0172, P0201, P0202,
P0203, P0204, P0300, P0336, P0337, P0351,
P0352, P0402, P0404, P0405, P0406, P0506,
P0507, P1404, and P0443 are not set.
S 3 second delay after conditions are met.
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 vehicle will operate in Open Loop.
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.

1F – 378IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0133
FRONT HEATED OXYGEN SENSOR (HO2S1) SLOW
RESPONSE
Circuit Description
The Engine Control Module (ECM) continuously monitors
the Front Heated Oxygen Sensor (HO2S1) activity for 100
seconds. During the monitor period, the ECM counts the
number of times that the HO2S1 switches from rich to lean
and from lean to rich and adds the amount of time it took
to complete all switches. With this information, an average
time for all switches can be determined. If the average time
to switch is too out of specification, a DTC P0133 will set.
If the HO2S1 pigtail wiring, connector, or terminal is dam-
aged, the entire HO2S1 assembly must be replaced. Do
not attempt to repair the wiring, connector, or terminals. In
order for the sensor to function properly, it must have a
clean air reference provided to it. This clean air reference
is obtained by way of the HO2S1 wire(s). Any attempt to
repair the wires, connector, or terminals could result in the
obstruction of the air reference and degrade HO2S1 per-
formance.
Conditions for Setting the DTCS HO2S1 average transition time between 0.3–0.6
volts, lean to rich is greater than 156 millisec-
onds(A/T) or rich to lean is greater than 140 milli-
seconds (M/T).
S Closed loop stoichiometry.
S Engine Coolant Temperature (ECT) is greater than
70°C (158°F).
S System voltage is greater than 10 volts.
S Engine run time is greater than 60 seconds.
S Purge Duty Cycle (DC) is less than 20%.
S The rpm is between 1600 and 4300.
S Airflow is between 9 and 40 g/sec.
S DTCs P0106, P0107, P0108, P0117, P0118,
P0122, P0123, P0131, P0132, P0134, P0135,
P1167, P0171, P1171, P0172, P0201, P0202,
P0203, P0204, P0300, P0336, P0337, P0351,
P0352, P0402, P0404, P0405, P0406, P0506,
P0507, P1404, and P0443 are not set.
S 2 second delay after conditions are met.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will illuminate
after three consecutive ignition cycle with a fail.

1F – 382IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0134
FRONT HEATED OXYGEN SENSOR (HO2S1) NO
ACTIVITY OR OPEN
Circuit Description
The Engine Control Module (ECM) supplies a voltage of
about 0.45 volts between terminals M12 and M29 (if mea-
sured with a 10 megohm digital voltmeter, this may read
as low as 0.32 volts). The Front Heated Oxygen Sensor
(HO2S1) varies the voltage within a range of about 1 volt
if the exhaust is rich, down through about 0.10 volts if the
exhaust is lean.
The sensor is like and open circuit and produces no volt-
age when it is below 315 °C (600 °F). An open sensor cir-
cuit or cold sensor causes Open Loop operation.
If the HO2S1 pigtail wiring, connector, or terminal is dam-
aged, the entire HO2S1 assembly must be replaced. Do
not attempt to repair the wiring, connector, or terminals. In
order for the sensor to function properly, it must have a
clean air reference provided to it. This clean air reference
is obtained by way of the HO2S1 wire(s). Any attempt to
repair the wires, connector or terminals could result in the
obstruction of the air reference and degrade the HO2S1
performance. Refer to”Front Heated Oxygen Sensor
(HO2S1)” in this section.Conditions for Setting the DTC
S HO2S1 voltage is between 420 and 480 mV.
S Engine Coolant Temperature (ECT) is greater than
60 °C (140 °F)
S System voltage is greater than 10 volts.
S Engine run time is greater than 60 seconds.
S Airflow is greater than 8 g/sec.
S DTCs P0106, P0107, P0108, P0117, P0118,
P0122, P0123, P0171, P0172, P0201, P0202,
P0203, P0204, P0300, P0336, P0337, P0351,
P0352, P0402, P0404, P0405, P0406, P0506,
P0507, P1404, and P0443 are not set.
S 3 second delay after exiting Decel Fuel Cut–off
(DFCO) mode.
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 vehicle will operate in Open Loop.

1F – 388IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0137
REAR HEATED OXYGEN SENSOR (HO2S2) LOW
VOLTAGE
Circuit Description
In order to control emissions, a catalytic converter is used
to convert harmful emissions into harmless water vapor
and carbon dioxide.
The Engine Control Module (ECM) has the ability to moni-
tor this process by using a Rear Heated Oxygen Sensor
(HO2S2). The HO2S2, located in the exhaust stream past
the catalytic converter, produces an output signal which in-
dicates the storage capacity of the catalyst. This in turn in-
dicates the catalyst’s ability to convert exhaust emissions
effectively. If the catalyst is functioning properly, the
HO2S2 signal will be far less active than the signal pro-
duced by the Front Heated Oxygen Sensor (HO2S1).
If the HO2S2 pigtail wiring, connector, or terminal is dam-
aged, the entire HO2S2 assembly must be replaced. Do
not attempt to repair the wiring, connector, or terminals. In
order for the sensor to function properly, it must have a
clean air reference provided to it. This clean air reference
is obtained by way of the HO2S2 wire(s). Any attempt to
repair the wires, connector, or terminals could result in the
obstruction of the air reference and degrade the HO2S2
performance.Conditions for Setting the DTC
S HO2S2 voltage is less than 0.05 volt in Closed
Loop control or less than 0.35 volt in Power Enrich-
ment (PE) mode.
S Engine Coolant Temperature (ECT) is greater than
60°C (140°F).
S System voltage is greater than 10 volts.
S Closed Loop test: 3 seconds delay after in Closed
Loop and air flow is greater than 9 g/sec.
S Power Enrichment test: Air/Fuel ration is less than
or equal to 13.5 and 3 seconds delay after in Power
Enrichment mode.
S DTCs P0106, P0107, P0108, P0117, P0118,
P0122, P0123, P0171, P0172, P0201, P0202,
P0203, P0204, P0300, P0336, P0337, P0351,
P0352, P0141, P0402, P0404, P0405, P0406,
P0506, P0507, P1404, and P0443 are not set.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will illuminate
after three consecutive ignition cycle with a fail.