2004 DAEWOO LACETTI engine coolant

1F – 142IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0133
FRONT HEATED OXYGEN SENSOR NO ACTIVITY
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 engine controls system is in closed loop.
S Engine Coolant Temperature is higher than
70°C(158°F). (1.4L DOHC)
S Engine Coolant Temperature is higher than
60°C(140°F). (1.6L DOHC)
S The mass air flow (MAF) is between 100mg/tdc and
250mg/tdc. (1.4L DOHC)
S The mass air flow (MAF) is between 60mg/tdc and
160mg/tdc. (1.6L DOHC)
S The engine speed is between 1,700 rpm and 2,200
rpm. (1.4L DOHC)
S The engine speed is between 1,800 rpm and 2,900
rpm. (1.6L DOHC)S The vehicle speed is between 40 km/h (24.9 mph)
and 60 km/h (37.3 mph). (1.4L DOHC)
S The vehicle speed is between 45 km/h (28.0 mph)
and 55 km/h (34.2 mph). (1.6L DOHC)
S The manifold air pressure is higher than 700hPa.
S The ignition is at 10 volts.
S The upstream O2 sensor periods higher than 1.6
seconds.
S A number of glitches higher than 5 during the test.
S DTCs P0107, P0108, P0112, P0113, P0117,
P0118, P0122, P0123, P0131, P0132, P0137,
P0138, P1671, P0300, P0335, P0336, P0341,
P0400, P0404, P0405, P0444, P0445 are NOT
SET.
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 vehicle will operate in Open Loop.

1F – 148IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0137
REAR HEATED OXYGEN SENSOR LOW VOLTAGE
Circuit Description
The engine control module (ECM) supplies a voltage of
about 450mm volts between the ECM terminals 14 and 16.
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 heated oxygen sensor voltage is below 0.07V
for at least 40 seconds.
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 full fuel cut off.
S Engine speed is less than 6,000rpm.
S The heated oxygen sensor voltage is between
0.352 and 0.499 at least 10 seconds.S DTCs P0107, P0108 and P0141 are NOT SET.
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 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 10 sec-
onds.
Diagnostic Aids
S Normal scan tool voltage varies between 0.1 volts
and 0.9 volts while in closed loop.
S Inspect the oxygen (O2) sensor wire. The O2 sen-
sor may be positioned incorrectly and contacting
the exhaust manifold.

ENGINE CONTROLS 1F – 153
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0140
REAR HEATED OXYGEN SENSOR NO ACTIVITY
Circuit Description
The engine control module (ECM) supplies a voltage of
about 450mm volts between the ECM terminals 64 and 16.
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 engine controls system is in closed loop.
S Engine Coolant Temperature is higher than 75°C
(167°F). (1.4L DOHC)
S Engine Coolant Temperature is higher than 70°C
(158°F). (1.6L DOHC)
S The engine speed is between 1,760 rpm and 2,368
rpm. (1.4L DOHC)
S The engine speed is between 1,300 rpm and 3,000
rpm. (1.6L DOHC)
S The vehicle speed is between 47 km/h (29.2 mph)
and 80 km/h (49.7 mph). (1.4L DOHC)
S The vehicle speed is between 26 km/h (16.2 mph)
and 54 km/h (33.6 mph). (1.6L DOHC)
S The manifold air pressure is higher than 700hPa.S No transition from rich side to lean side or lean side
to rich side during 7.8 seconds even with a forcing
of O2 sensor controller.
S DTCs P0107, P0108, P0112, P0113, P0117,
P0118, P0122, P0123, P0137, P0138, P1671,
P0300, P0335, P0336, P0341, P0400, P0404,
P0405, P0644, P0645 are NOT SET.
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 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.
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.

1F – 156IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0141
REAR HEATED OXYGEN SENSOR HEATER
MALFUNCTION
Circuit Description
The engine control module (ECM) supplies a voltage of
about 450mm volts between the ECM terminals 14 and 16.
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 heated O2 sensor heater resistance is less
than 0 W or greater than 160 W. (1.4L DOHC)
S The heated O2 sensor heater resistance is less
than 10 W or greater than 30 W. (1.6L DOHC)
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 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 10 sec-
onds.
Diagnostic Aids
S Normal scan tool voltage varies between 0.1volts
and 0.9 volts while in closed loop.
S Inspect the oxygen (O2) sensor wire. The O2 sen-
sor may be positioned incorrectly and contacting
the exhaust manifold.
S Check for an intermittent ground in the wire be-
tween the O2 sensor and the engine control mod-
ule.
S Perform an injector 2alance test to determine if a
restricted fuel injector may be causing the lean con-
dition.
S Vacuum of crankcase leaks will cause a lean run-
ning condition.

1F – 158IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0171
FUEL TRIM SYSTEM TOO LEAN
System Description
If the adaptation value threshold is permanently exceed-
ed, the deviation of the adaptive terms enables to detect
a slow default coming out. Two time counters (one for the
rich side and another one for the lean side) are increased
while the lambda controller exceeds the adaptation
thresholds. As soon as one of the time counters reaches
its maximum value, the error is detected.
The aim of this test is to simulate a failure that would result
in exceeding the adaptive terms. Two kinds of failure must
be created.
S A lean side deviation: P0171
S A rich side deviation : P0172
It is thus necessary to determine, for each kind of failure,
the limit good and the limit bad. For a given failure, mea-
sure the emission threshold until the legal emission
thresholds are exceeded.
Note that the problem is due to the emission thresholds re-
quired, it is not simple to disturb the system so that the
emission thresholds will be exceeded. The tuning has
been made thanks to a dedicated calibration but, as such
a procedure is not permitted by the regulation, it is neces-
sary to create some material malfunction (fuel pressure
regulator, fuel injector, air leakage...).
Conditions for Setting the DTC
S DTCs P0107, P0108, P0112, P0113, P0117,
P0118, P0122, P0123, P0131, P0132, P0337,
P0338, P0341, P0342, P0400, P1319, P1402,
P1404, P1405, P1671 and P1672 are not set.
S Coolant temperature is greater than 20°C (68°F).
(1.4L DOHC)
S Coolant temperature is greater than 80°C (176°F).
(1.6L DOHC)
S Manifold Absolute Pressure (MAP) is greater than
70 kPa (10.2 psi).
S System is in closed loop.
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.
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
Important : After repairs, use the scan tool Fuel Trim Re-
set function to reset the long–term fuel trim to 128 (0%).
S Fuel pressure – The system will be lean if the pres-
sure is too low. It may be necessary to monitor fuel
pressure while driving the vehicle at various road
speeds and/or loads to confirm.
S Map sensor – An output that causes the ECM to
sense a lower than normal manifold pressure (high
vacuum) can cause the system to go lean. Discon-
necting the MAP sensor will allow the ECM to sub-
stitute a fixed (default) value for the MAP sensor. If
the lean condition is gone when the sensor is dis-
connected, substitute a known good sensor and
recheck.
S Fuel contamination – Water, in even small amounts,
near the in–tank fuel pump inlet can be delivered to
the injector. The water causes a lean exhaust and
can set DTC P0171.
Check for poor O2S or MAP sensor connection at the
ECM. Inspect the harness connectors for the following
conditions:
S Backed–out terminals
S Improper mating
S Broken locks
S Improperly formed
S Damaged terminals
S Poor terminal–to–wire connection
Inspect the wiring harness for damage. If the harness ap-
pears to be OK, observe the O2S display on the scan tool
while moving the connectors and the wiring harness re-
lated to the engine harness. A change in the display will
indicate the location of the fault.
Check the brake power booster check valve for possible
leaks.

1F – 162IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0172
FUEL TRIM SYSTEM TOO RICH
System Description
If the adaptation value threshold is permanently exceed-
ed, the deviation of the adaptive terms enables to detect
a slow default coming out. Two time counters (one for the
rich side and another one for the lean side) are increased
while the lambda controller exceeds the adaptation
thresholds. As soon as one of the time counters reaches
its maximum value, the error is detected.The aim of this
test is to simulate a failure that would result in exceeding
the adaptive terms. Two kinds of failure must be created.
S A lean side deviation: P0171
S A rich side deviation : P0172
It is thus necessary to determine, for each kind of failure,
the limit good and the limit bad. For a given failure, mea-
sure the emission threshold until the legal emission
thresholds are exceeded.Note that the problem is due to
the emission thresholds required, it is not simple to disturb
the system so that the emission thresholds will be exceed-
ed. The tuning has been made thanks to a dedicated cal-
ibration but, as such a procedure is not permitted by the
regulation, it is necessary to create some material mal-
function (fuel pressure regulator, fuel injector, air leak-
age...).
Conditions for Setting the DTC
S DTCs P0107, P0108, P0112, P0113, P0117,
P0118, P0122, P0123, P0131, P0132, P0337,
P0338, P0341, P0342, P0400, P1319, P1402,
P1404, P1405, P1671 and P1672 are not set.
S Coolant temperature is greater than 20°C (68°F).
(1.4L DOHC)
S Coolant temperature is greater than 80°C (176°F).
(1.6L DOHC)
S Manifold Absolute Pressure (MAP) is greater than
70 kPa (10.2 psi).
S System is in closed loop.
Action Taken When the DTC SetsS 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.
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
Important : After repairs, use the scan tool Fuel Trim Re-
set function to reset the long–term fuel trim to 128 (0%).
Check for poor connection at the ECM. Inspect the har-
ness connectors for the following conditions:
S Backed–out terminals.
S Improper mating.
S Broken locks.
S Improperly formed.
S Damaged terminals.
S Poor terminal–to–wire connection.
Inspect the wiring harness for damage. If the harness ap-
pears to be OK, observe the O2S display on the scan tool
while moving the connectors and the wiring harness re-
lated to the engine harness. A change in the display will
indicate the location of the fault.
If a DTC P1404 is also set, check the 5 volt reference cir-
cuits for a short to voltage.
Check for a restricted exhaust system.
A shorted 5 volt reference circuit may cause a DTC P0172
to set. Check the 5 volt reference sensors for abnormal
readings.
DTC P0172 – Fuel Trim System Too Rich
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. Install the scan tool to the Data Link Connector
(DLC).
2. Turn the ignition ON.
Are any component related Diagnostic Trouble
Codes (DTCs) set?–Go to
applicable DTC
tableGo to Step 3

ENGINE CONTROLS 1F – 195
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0327
KNOCK SENSOR CIRCUIT FAULT (1.4L DOHC)
Circuit Description
The knock sensor (KS) system is used to detect engine
detonation, allowing the engine control module (ECM) to
retard ignition control spark timing based on the KS signal
being received. The KS produces an AC signal so that un-
der a no knock condition the signal on the KS circuit mea-
sures about 0.007V AC. The KS signal’s amplitude and
frequency depend upon the amount of knock being experi-
enced. The ECM contains a non–replaceable knock filter
module called a signal–to–noise enhancement filter
(SNEF) module. This filter module in the ECM determines
whether knock is occurring by comparing the signal level
on the KS circuit with the voltage level on the noise chan-
nel. The noise channel allows the ECM to reject any false
knock signal by knowing the amount of normal engine me-
chanical noise present. Normal engine noise varies de-
pending on engine speed and load. When the ECM deter-
mines that an abnormally low noise channel voltage level
is being experienced, a DTC P0327 will set.
Conditions for Setting the DTC
S The knock sensor SPI bus in failure during 8 sec-
onds.
Or
S The knock sensor voltage is less than 0.3V.
S The engine coolant temperature is greater than
60°C (145°F).
S The engine speed is greater than 1,500 rpm.
S The mass air flow is higer than 180mg/tdc.
Or
S When difference between a original signal valve
and filtering valve is less than 5%.S The engine coolant temperature is greater than
60°C (145°F).
S The mass air flow is greater than 180mg/tdc.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will not illumi-
nate.
S The ECM will store wnditions which were present
when the DTC was set as Failure Records data
only.
S This information will not be stored in the Freeze
Frame data.
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 and correct any abnormal engine noise before us-
ing the diagnostic table.
Any circuitry that is suspected as causing engine noise
complaint should be thoroughly checked for the following
conditions :
S Backed–out terminals
S Improper mating
S Broken locks
S Improperly formed
S Damaged terminals
S Poor terminal–to–wire connection
S Physical damage to the wiring harness

1F – 198IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0327
KNOCK SENSOR CIRCUIT FAULT (1.6L DOHC)
Circuit Description
The knock sensor (KS) system is used to detect engine
detonation, allowing the transaxle control module
(TCM)/engine control module (ECM) to retard ignition con-
trol spark timing based on the KS signal being received.
The KS produces an AC signal so that under a no knock
condition the signal on the KS circuit measures about
0.007V AC. The KS signal’s amplitude and frequency de-
pend upon the amount of knock being experienced. The
ECM contains a non–replaceable knock filter module
called a signal–to–noise enhancement filter (SNEF) mod-
ule. This filter module in the ECM determines whether
knock is occurring by comparing the signal level on the KS
circuit with the voltage level on the noise channel. The
noise channel allows the ECM to reject any false knock
signal by knowing the amount of normal engine mechani-
cal noise present. Normal engine noise varies depending
on engine speed and load. When the ECM determines that
an abnormally low noise channel voltage level is being ex-
perienced, a DTC P0327 will set.
Conditions for Setting the DTC
S The knock sensor SPI bus in failure during 10 sec-
onds.
Or
S The knock sensor voltage is less than 0.3V.
S The engine coolant temperature is greater than
60°C(145°F).
S The engine speed is greater than 1,500rpm.
S The mass air flow is higer than 180mg/tdc.
Or
S When difference between a original signal valve
and filtering valve is less than 5%.S The engine coolant temperature is greater than
60°C(145°F).
S The mass air flow is greater than 170mg/tdc.
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.
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
Check and correct any abnormal engine noise before us-
ing the diagnostic table.
Any circuitry that is suspected as causing engine noise
complaint should be thoroughly checked for the following
conditions :
S Backed–out terminals
S Improper mating
S Broken locks
S Improperly formed
S Damaged terminals
S Poor terminal–to–wire connection
S Physical damage to the wiring harness