2004 DAEWOO LACETTI tow

1F – 146IENGINE CONTROLS
DAEWOO V–121 BL4
S Damaged harness
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. This step determines if DTC P0135 is the result of
a hard failure or an intermittent condition. With the
ignition ON, engine OFF, the HO2S1 voltage dis-played on the scan tool should change within sever-
al minutes toward 0 or 1 volt, indicating that the
heater is working properly.
3. Probing terminal 4 of the HO2S1 connector verifies
if voltage is available to the HO2S1 heater.
4. If voltage is available at the connector, than it be-
comes a good voltage source to check for a ground
at terminal 3.
5. Determines if voltage is not available at the HO2S1
due to an open in the HO2S1 fuse or open ignition
feed circuit. If the fuse is open, determine if it was
due to a short in the ignition feed circuit before re-
placing the fuse.
DTC P0135 – Front Heated Oxygen Sensor Heater Circuit Not
Functioning
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Is the check complete?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
2Notice : If the engine has just been operating, allow
the engine to cool for about one–half hour before
proceeding.
1. Turn the ignition switch ON, with the engine
OFF.
2. Install a scan tool.
Does the Front Heated Oxygen Sensor (HO2S1)
voltage gradually change toward the specified volt-
age?0 v or 1 vGo to Step 13Go to Step 3
31. Disconnect the HO2S1 electrical connector.
2. With a test light connected to ground, probe
the ignition feed circuit, terminal 2 of the con-
nector.
Does the test light illuminate?–Go to Step 4Go to Step 5
4Connect a test light between the ignition feed and
ground circuits, terminal 2 and 3 of the connector.
Does the test light illuminate?–Go to Step 6Go to Step 7
5Inspect the fuse in the engine fuse block.
Is the fuse open?–Go to Step 8Go to Step 9
6Check the connections terminal 2 and 1 at the
HO2S2 connector and repair as necessary.
Is a repair necessary?–Go to Step 13Go to Step 10
7Check the connections terminal 4 at the HO2S1 con-
nector and repair as necessary.
Is a repair necessary?–Go to Step 13Go to Step 11
81. Check for a short to ground in the HO2S1 igni-
tion feed circuit and repair as necessary?
2. Replace open fuse.
Is the action complete?–Go to Step 13–

1F – 386IENGINE CONTROLS
DAEWOO V–121 BL4
S Damaged harness
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. This step determines if DTC P0135 is the result of
a hard failure or an intermittent condition. With the
ignition ON, engine OFF, the HO2S1 voltage dis-played on the scan tool should change within sever-
al minutes toward 0 or 1 volt, indicating that the
heater is working properly.
3. Probing terminal 2 of the HO2S1 connector verifies
if voltage is available to the HO2S1 heater.
4. If voltage is available at the connector, than it be-
comes a good voltage source to check for a ground
at terminal 3.
5. Determines if voltage is not available at the HO2S1
due to an open in the HO2S1 fuse or open ignition
feed circuit. If the fuse is open, determine if it was
due to a short in the ignition feed circuit before re-
placing the fuse.
DTC P0135 – Front Heated Oxygen Sensor (HO2S1) Heater Circuit
Not Functioning
StepActionValue(s)YesNo
1Perform an On–Board Diagnostic (EOBD) System
Check.
Is the check complete?–Go to Step 2Go to
”On–Board
Diagnostic Sys-
tem Check”
2Notice : If the engine has just been operating, allow
the engine to cool for about one–half hour before
proceeding.
1. Turn the ignition switch ON, with the engine
OFF.
2. Install a scan tool.
Does the Front Heated Oxygen Sensor (HO2S1)
voltage gradually change toward the specified volt-
age?0 v or 1 vGo to Step 13Go to Step 3
31. Disconnect the HO2S1 electrical connector.
2. With a test light connected to ground, probe
the ignition feed circuit, terminal 4 of the con-
nector.
Does the test light illuminate?–Go to Step 4Go to Step 5
4Connect a test light between the ignition feed and
ground circuits, terminal 4 and 3 of the connector.
Does the test light illuminate?–Go to Step 6Go to Step 7
5Inspect the fuse in the engine fuse block.
Is the fuse open?–Go to Step 8Go to Step 9
6Check the connections terminal 4 and 1 at the
HO2S1 connector and repair as necessary.
Is a repair necessary?–Go to Step 13Go to Step 10
7Check the connections terminal 3 at the HO2S1 con-
nector and repair as necessary.
Is a repair necessary?–Go to Step 13Go to Step 11
81. Check for a short to ground in the HO2S1 igni-
tion feed circuit and repair as necessary?
2. Replace open fuse.
Is the action complete?–Go to Step 13–

1F – 398IENGINE CONTROLS
DAEWOO V–121 BL4
Diagnostic Aids
An intermittent may be caused by a rubbed–through wire
insulation or a wire contacting the exhaust.
Check for a poor connection or a damaged harness – in-
spect the harness connectors for the following conditions:
S Improper mating
S Broken locks
S Improperly formed
S Damaged terminals
S Poor terminal–to–wire connection
S Damaged harness
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. This step determines if DTC P0141 is the result of
a hard failure or an intermittent condition. With the
ignition ON, engine OFF, the HO2S2 voltage dis-
played on the scan tool should change within sever-
al minutes toward 0 or 1 volt, indicating that the
heater is working properly.
3. Probing terminal D of the HO2S2 connector verifies
if voltage is available to the HO2S2 heater.
4. If voltage is available at the connector, than it be-
comes a good voltage source to check for a ground
at terminal 3.
5. Determines if voltage is not available at the HO2S2
due to an open in the HO2S2 fuse or open ignition
feed circuit. If the fuse is open, determine if it was
due to a short in the ignition feed circuit before re-
placing the fuse.
DTC P0141 – Rear Heated Oxygen Sensor (HO2S2) Heater Circuit
Not Functioning
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. Turn the ignition OFF.
2. Disconnect the Rear Heated Oxygen Sensor
(HO2S2) connector.
3. Turn the ignition ON.
4. Using a voltmeter, measure the voltage at ter-
minal 4 of HO2S2 and ground.
Is the voltage within the specified value?11–14 VGo to Step 3Go to
”Main Relay
Circuit Check”
31. Turn the ignition OFF.
2. Disconnect the HO2S2 connector.
3. Check the connections at HO2S2 connector,
terminal 3 and 4 and repair as needed.
Is the repair complete?–Go to Step 10Go to Step 4
4Disconnect the Engine control Module (ECM) con-
nector.
Check the connection at the ECM connector, termi-
nal M2 and repair as needed.–Go to Step 10Go to Step 5
51. Using ohmmeter, measure the resistance be-
tween terminal 3 of the HO2S2 and terminal
M2 of the ECM.
Is the resistance equal to the specified value?
1. Using a voltmeter, measure the voltage be-
tween terminal M2 of the ECM and ground.
Is the voltage within the specified value?0 Ω

0 VGo to Step 7Go to Step 6
6Repair an open or short to voltage circuit.
Is the repair complete?–Go to Step 10–

1F – 452IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0336
58X CRANK POSITION SENSOR EXTRA/MISSING
PULSES
Circuit Description
The 58X reference signal is produced by the Crankshaft
Position (CKP) sensor. During one crankshaft revolution,
58 crankshaft pulses will be produced. The Engine Control
Module (ECM) uses the 58X reference signal to calculate
engine rpm and CKP. The ECM constantly monitors the
number of pulses on the 58X reference circuit and
compares them to the number of Camshaft Position
(CMP) signal pulses being received. If the ECM receives
and incorrect number of pulses on the 58X reference cir-
cuit, Diagnostic Trouble Code (DTC) P0336 will set.
Conditions for Setting the DTC
S Engine is running.
S Extra or missing pulses detected between consecu-
tive 58X reference pulses.
S Number of extra or missing teeth is greater than or
equal to 2 per revolution.
S Above condition is detected in 10 of 100 crankshaft
rotations.
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
buffer.
S A history DTC is stored.
Conditions for Clearing the MIL/DTCS The MIL will turn OFF after four consecutive igni-
tion cycles in which the diagnostic runs without a
fault.
S A history DTC will clear after 40 consecutive warm–
up cycles have occurred without a fault.
S The DTC(s) can be cleared using the scan tool.
S Disconnecting the ECM battery feed for more than
10 seconds.
Diagnostic Aids
An intermittent may be caused by a poor connection,
rubbed–through wire insulation or a wire broken inside the
insulation. Check for:
S Poor connection – Inspect the ECM harness and
connectors for improper mating, broken locks, im-
properly formed or damaged terminals, and poor
terminal–towire connections.
S Damaged harness – Inspect the wiring harness for
damage. If the harness appears to be OK, discon-
nect the ECM, turn the ignition ON and observe a
voltmeter connected to the 58X reference circuit at
the ECM harness connector while moving the con-
nectors and the wiring harnesses related to the
ECM. A change in voltage will indicate the location
of the fault.
S Reviewing the Failure Records vehicle mileage
since the diagnostic test last failed may help deter-
mine how often the condition that caused the DTC
to be set occurs. This may assist in diagnosing the
condition.

ENGINE CONTROLS 1F – 455
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0337
58X CRANK POSITION SENSOR NO SIGNAL
Circuit Description
The 58X reference signal is produced by the Crankshaft
Position (CKP) sensor. During one crankshaft revolution,
58 crankshaft pulses will be produced. The Engine Control
Module (ECM) uses the 58X reference signal to calculate
engine rpm and CKP. The ECM constantly monitors the
number of pulses on the 58X reference circuit and
compares them to the number of Camshaft Position
(CMP) signal pulses being received. If the ECM does not
receive any 58X reference pulses on the 58X reference
circuit while cranking, Diagnostic Trouble Code (DTC)
P0337 will set.
Conditions for Setting the DTC
S 58X reference pulse not seen during cranking.
S DTCs P0341 and P0342 are not set.
S Change in voltage drop is greater than 0.5 volts and
change in Manifold Absolute Pressure (MAP) is
greater than 0.05kPa (0.07 psi).
S 58X reference pulse not seen for 0.078 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
buffer.
S A history DTC is stored.
Conditions for Clearing the MIL/DTCS The MIL will turn OFF after four consecutive igni-
tion cycles in which the diagnostic runs without a
fault.
S A history DTC will clear after 40 consecutive warm–
up cycles have occurred without a fault.
S The DTC(s) can be cleared using the scan tool.
S Disconnecting the ECM battery feed for more than
10 seconds.
Diagnostic Aids
An intermittent may be caused by a poor connection,
rubbed–through wire insulation or a wire broken inside the
insulation. Check for:
S Poor connection – Inspect the ECM harness and
connectors for improper mating, broken locks, im-
properly formed or damaged terminals, and poor
terminal–towire connections.
S Damaged harness – Inspect the wiring harness for
damage. If the harness appears to be OK, discon-
nect the ECM, turn the ignition ON and observe a
voltmeter connected to the 58X reference circuit at
the ECM harness connector while moving the con-
nectors and the wiring harnesses related to the
ECM. A change in voltage will indicate the location
of the fault.
S Reviewing the Failure Records vehicle mileage
since the diagnostic test last failed may help deter-
mine how often the condition that caused the DTC
to be set occurs. This may assist in diagnosing the
condition.

1F – 464IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0351
IGNITION CONTROL CIRCUIT A FAULT (CYLINDER 1 & 4)
Circuit Description
The Engine Control Module (ECM) provides a ground for
the electronic spark timing A circuit. When the ECM re-
moves the ground path of the ignition primary coil, the
magnetic field produced by the coil collapses. The collaps-
ing magnetic field produces a voltage in the secondary coil
which fires the spark plug.
The circuit between the ECM and the electronic ignition
system ignition coil is monitored for an open circuit, short
to voltage, and short to ground. When the ECM detects a
problem in the electronic spark timing A circuit, it will set
Diagnostic Trouble Code (DTC) P0351.
Conditions for Setting the DTC
S Monitor fault feedback signal.
S Ignition ON.
S Fault flag increments fail count.
S Must receive more than 200 failures within 255 test
cycles.
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 Low speed coolant fan turns on.
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
An intermittent may be caused by a poor connection,
rubbed–through wire insulation or a wire broken inside the
insulation. Check for:
S Poor connection – Inspect the ECM harness and
connectors for improper mating, broken locks, im-
properly formed or damaged terminals, and poor
terminal–towire connection.

1F – 466IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0352
IGNITION CONTROL CIRCUIT B FAULT (CYLINDER 2 & 3)
Circuit Description
The Engine Control Module (ECM) provides a ground for
the electronic spark timing A circuit. When the ECM re-
moves the ground path of the ignition primary coil, the
magnetic field produced by the coil collapses. The collaps-
ing magnetic field produces a voltage in the secondary coil
which fires the spark plug.
The circuit between the ECM and the electronic ignition
system ignition coil is monitored for an open circuit, short
to voltage, and short to ground. When the ECM detects a
problem in the electronic spark timing A circuit, it will set
Diagnostic Trouble Code (DTC) P0351.
Conditions for Setting the DTC
S Monitor fault feedback signal.
S Ignition ON.
S Fault flag increments fail count.
S Must receive more than 200 failures within 255 test
cycles.
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 Low speed coolant fan turns on.
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
An intermittent may be caused by a poor connection,
rubbed–through wire insulation or a wire broken inside the
insulation. Check for:
S Poor connection – Inspect the ECM harness and
connectors for improper mating, broken locks, im-
properly formed or damaged terminals, and poor
terminal–towire connection.

1F – 468IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0401
EXHAUST GAS RECIRCULATION INSUFFICIENT FLOW
Circuit Description
An Exhaust Gas Recirculation (EGR) system is used to
lower Nitrogen Oxide (NOx) emission levels caused by
high combustion temperatures. It accomplishes this by
feeding small amounts of exhaust gases back into the
combustion chamber. When the air/fuel mixture is diluted
with the exhaust gases, combustion temperatures are re-
duced
A linear EGR valve is used on this system. The linear EGR
valve is designed to accurately supply exhaust gases to
the engine without the use of intake manifold vacuum. The
valve controls exhaust flow going into the intake manifold
from the exhaust manifold through an orifice with an En-
gine Control Module (ECM) controlled pintle. The ECM
controls the pintle position using inputs from the Throttle
Position (TP) and Manifold Absolute Pressure (MAP) sen-
sors. The ECM then commands the EGR valve to operate
when necessary by controlling an ignition signal through
the ECM. This can be monitored on a scan tool as the De-
sired EGR Position.
The ECM monitors the results of its command through a
feedback signal. By sending a 5 volt reference and a
ground to the EGR valve, a voltage signal representing the
EGR valve pintle position is sent to the ECM. This feed-
back signal can also be monitored on a scan tool and is the
actual position of the EGR pintle. The Actual EGR Position
should always be near the commanded or Desired EGR
Position.
This diagnostic will determine if there is a reduction in EGR
flow.
Conditions for Setting the DTC
S DTCs P0106, P0107, P0108, P0117, P0118,
P0122, P0123, P0201, P0202, P0203, P0204,
P0351, P0352, P0402, P0404, P1404, P0405,
P0406 and P0502 are not set.
S Test in Decel Fuel Cutoff (DFCO) mode.
S Barometric Pressure (BARO) is greater than 72
kPa (10.4 psi).
S Vehicle speed is greater than 18 km/h (11.2
mph).
S A/C clutch/transmission clutch are unchanged.
S Rpm is between 1400 and 3000 for manual
transaxle.
S Rpm is between 1300 and 2900 for automatic
transaxle.
S Compensated MAP is with 10.3 to 32 kpa (1.5 to
4.6 psi) range.
S Start test
S Throttle position (TP) sensor is less then 1%.
S EGR is less than 1%.
S Change in MAP is less than 1.0 kpa (0.15 psi)Note : Test will be aborted when:
S Change in vehicle speed is greater than 5km/h (3.1
mph).
S Rpm is increased more than 75.
S EGR opened less than 90% commanded position.
Action Taken When the DTC Sets
S The Malfunction Indicator Lamp (MIL) will not illumi-
nate.
S The ECM will store conditions which were present
when the DTC set as Failure Records data only.
This information will not be stored in the Freeze
Frame data.
S A history Diagnostic Trouble Code (DTC) is stored.
S EGR is disabled.
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
The EGR Decel Filter value can be a great aid in determin-
ing if a problem exists and to verify repairs. The EGR De-
cel Filter is an average of the difference in the expected
MAP change and the actual MAP change caused by open-
ing the EGR valve during a deceleration, and is used to de-
termine when the MIL is illuminated. By driving the vehicle
up to approximately 97 km/h (60 mph) and decelerating to
32 km/h (20 mph), it can be determined if the EGR system
is OK, partially restricted, or fully restricted.
A more negative number (less than –3) indicates that the
system is working normally, whereas a positive number in-
dicates that the system is being restricted and that the ex-
pected amount of EGR flow is was not seen. A number
that falls between negative 3 and positive 2 indicates that
the system is partially restricted but not restricted enough
to cause an emissions impact.
The EGR Decel Filter value should always be at –3 or low-
er. If the EGR Decel Filter number becomes more positive
(towards 0 or more), then the EGR system is becoming re-
stricted. Look for possible damage to the EGR pipe or for
a restriction caused by carbon deposits in the EGR pas-
sages or on the EGR valve.
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