2004 DAEWOO LACETTI Ground

ENGINE CONTROLS 1F – 181
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0268
INJECTOR 3 HIGH VOLTAGE
Circuit Description
The transaxle control module(TCM)/engine control mod-
ule (ECM) has four individual injector driver circuits, each
of which controls an injector. When a driver circuit is
grounded by the ECM, the injector is activated. The ECM
monitors the current in each driver circuit. The ECM mea-
sures a voltage drop through a fixed resistor and controls
it. The voltage on each driver is monitored to detect a fault.
If the voltage is not what the ECM expects to monitor on
the circuit, a Diagnostic Trouble Code (DTC) is set. This
DTC detects a low voltage and/or an open circuit and high
voltage conditions for low–side drive injector outputs.
Conditions for Setting the DTC
S The injector 3 circuit is a short to battery condition
exists.
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 Records buffers.S A history DTC is stored.
Conditions for Clearing the MIL/DTC
S The MIL will turn off after 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
An injector driver circuit that is open or shorted to voltage
will causes a DTC P0268 to set. It will also cause a misfire
due to an inoperative injector. A misfire DTC should also
be set indicating which injector is inoperative.
Long–term and short–terms fuel trims that are excessively
high or low are a good indication that an injector is mal-
functioning. Refer to ”Fuel Injector Balance Test” in this
section to check for malfunctioning injectors.
The injector resistance tested at the ECM connection is
slightly more than it tested directly at the injector because
it includes resistance of the harness wires. The normal val-
ue is about 13.5W.

ENGINE CONTROLS 1F – 183
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0270
INJECTOR 4 LOW VOLTAGE
Circuit Description
The transaxle control module(TCM)/engine control mod-
ule (ECM) has four individual injector driver circuits, each
of which controls an injector. When a driver circuit is
grounded by the ECM, the injector is activated. The ECM
monitors the current in each driver circuit. The ECM mea-
sures a voltage drop through a fixed resistor and controls
it. The voltage on each driver is monitored to detect a fault.
If the voltage is not what the ECM expects to monitor on
the circuit, a Diagnostic Trouble Code (DTC) is set. This
DTC detects a low voltage and/or an open circuit and high
voltage conditions for low–side drive injector outputs.
Conditions for Setting the DTC
S The injector 4 circuit is an open or a short to ground
condition exists.
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 Records buffers.S A history DTC is stored.
Conditions for Clearing the MIL/DTC
S The MIL will turn off after 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
An injector driver circuit that is open or shorted to voltage
will causes a DTC P0270 to set. It will also cause a misfire
due to an inoperative injector. A misfire DTC should also
be set indicating which injector is inoperative.
Long–term and short–terms fuel trims that are excessively
high or low are a good indication that an injector is mal-
functioning. Refer to ”Fuel Injector Balance Test” in this
section to check for malfunctioning injectors.
The injector resistance tested at the ECM connection is
slightly more than it tested directly at the injector because
it includes resistance of the harness wires. The normal val-
ue is about 13.5W.

1F – 184IENGINE CONTROLS
DAEWOO V–121 BL4
DTC P0270 – Injector 4 Low Voltage
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”
2Does the engine start?–Go to Step 3Go to
”Engine Cranks
But Will Not
Run”
31. Install a scan tool and clear the Diagnostic
Trouble Codes (DTCs).
2. Idle the engine for one minuet.
Does DTC P0270 reset?–Go to Step 5Go to Step 4
41. Review the Freeze Frame data with the ignition
ON and the engine OFF and note the parame-
ters.
2. Operate the vehicle within the Freeze Frame
conditions as notes.
Does DTC P0270 reset?–Go to Step 5Go to
”Diagnostic
Aids”
51. Turn the ignition switch to LOCK.
2. Check for short to ground in the wire between
the injector 4 connector terminal 2 and ECM
connector terminal 89.
Is the problem found?–Go to Step 7Go to Step 6
61. Turn the ignition switch to LOCK.
2. Check for short to ground in the wire between
the injector 4 connector terminal 1 and battery
positive.
Is the problem found?–Go to Step 7Go to Step 8
71. Repair the wire or the connector terminal as
needed.
2. Clear any DTCs from ECM.
3. Perform the Diagnostic System Check.
Is the repair complete?–System OK–
81. Replace the injector valve.
2. Clear any DTCs from ECM.
3. Perform the Diagnostic System Check.
Does DTC P0270 reset?–Go to Step 9System OK
91. Turn the ignition switch to LOCK.
2. Replace the ECM.
3. Perform the Diagnostic System Check.
Is the repair complete?–Go to Step 10–
10Check if any additional DTCs are set.
Are any DTCs displaced that have not been diag-
nosed?–Go to
applicable DTC
tableSystem OK

ENGINE CONTROLS 1F – 185
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0271
INJECTOR 4 HIGH VOLTAGE
Circuit Description
The transaxle control module(TCM)/engine control mod-
ule (ECM) has four individual injector driver circuits, each
of which controls an injector. When a driver circuit is
grounded by the ECM, the injector is activated. The ECM
monitors the current in each driver circuit. The ECM mea-
sures a voltage drop through a fixed resistor and controls
it. The voltage on each driver is monitored to detect a fault.
If the voltage is not what the ECM expects to monitor on
the circuit, a Diagnostic Trouble Code (DTC) is set. This
DTC detects a low voltage and/or an open circuit and high
voltage conditions for low–side drive injector outputs.
Conditions for Setting the DTC
S The injector 4 circuit is a short to battery condition
exists.
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 Records buffers.S A history DTC is stored.
Conditions for Clearing the MIL/DTC
S The MIL will turn off after 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
An injector driver circuit that is open or shorted to voltage
will causes a DTC P0271 to set. It will also cause a misfire
due to an inoperative injector. A misfire DTC should also
be set indicating which injector is inoperative.
Long–term and short–terms fuel trims that are excessively
high or low are a good indication that an injector is mal-
functioning. Refer to ”Fuel Injector Balance Test” in this
section to check for malfunctioning injectors.
The injector resistance tested at the ECM connection is
slightly more than it tested directly at the injector because
it includes resistance of the harness wires. The normal val-
ue is about 13.5W.

ENGINE CONTROLS 1F – 189
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
71. Turn the engine OFF.
2. Install a fuel pressure gauge to the fuel rail.
3. Observe the fuel pressure with the engine run-
ning.
Is the fuel pressure within the specified value?284–325 kPa
(41–47 psi)Go to Step 8Go to
”Fuel System
Diagnosis”
8Check the fuel for contamination.
Is the fuel OK?–Go to Step 9Go to Step 10
9Check for a basic engine problem and repair as nec-
essary.
Is the repair complete?–Go to Step 27–
10Replace the contaminated fuel.
Is the repair complete?–Go to Step 27–
111. Turn the engine OFF.
2. Disconnect the fuel injector harness connector.
3. Install a spark tester on cylinder #1 spark plug
cable.
4. Crank the engine and check for spark.
5. Repeat the above procedure on cylinders #2,
#3 and #4.
Is a spark observed on all four spark plug cables?–Go to Step 12Go to Step 20
12Replace any malfunctioning spark plugs if neces-
sary.
Is the repair complete?–Go to Step 27Go to Step 13
131. Turn the engine OFF.
2. Disconnect the fuel injector connectors from
the injectors.
3. Install an injector test light on the injector har-
ness connector for the cylinders that had mis-
fired.
4. Crank the engine and note the test light.
Does the injector test light blink?–Go to Step 14Go to Step 15
14Perform the Fuel Injector Balance Test.
Are the fuel injectors OK?–Go to Step 9Go to Step 16
151. Disconnect the injector test light.
2. With a test light connected to ground, probe
the ignition feed terminal 2 of the injector har-
ness connector for each cylinder that had mis-
fire.
3. Crank the engine.
Does the test light illuminate?–Go to Step 17Go to Step 19
16Replace any malfunctioning fuel injectors.
Is the repair complete?Go to Step 27–
17Check the affected fuel injector driver circuit at termi-
nals 59, 89, 90, and 60 for an open, short, or short
to voltage.
Is a problem found?–Go to Step 18Go to Step 24
18Repair the open or the shorted fuel injector driver cir-
cuit.
Is the repair complete?–Go to Step 27–

ENGINE CONTROLS 1F – 193
DAEWOO V–121 BL4
StepNo Yes Value(s) Action
71. Turn the engine OFF.
2. Install a fuel pressure gauge to the fuel rail.
3. Observe the fuel pressure with the engine run-
ning.
Is the fuel pressure within the specified value?284–325 kPa
(41–47 psi)Go to Step 8Go to
”Fuel System
Diagnosis”
8Check the fuel for contamination.
Is the fuel OK?–Go to Step 9Go to Step 10
9Check for a basic engine problem and repair as nec-
essary.
Is the repair complete?–Go to Step 27–
10Replace the contaminated fuel.
Is the repair complete?–Go to Step 27–
111. Turn the engine OFF.
2. Disconnect the fuel injector harness connector.
3. Install a spark tester on cylinder #1 spark plug
cable.
4. Crank the engine and check for spark.
5. Repeat the above procedure on cylinders #2,
#3 and #4.
Is a spark observed on all four spark plug cables?–Go to Step 12Go to Step 20
12Replace any malfunctioning spark plugs if neces-
sary.
Is the repair complete?–Go to Step 27Go to Step 13
131. Turn the engine OFF.
2. Disconnect the fuel injector connectors from
the injectors.
3. Install an injector test light on the injector har-
ness connector for the cylinders that had mis-
fired.
4. Crank the engine and note the test light.
Does the injector test light blink?–Go to Step 14Go to Step 15
14Perform the Fuel Injector Balance Test.
Are the fuel injectors OK?–Go to Step 9Go to Step 16
151. Disconnect the injector test light.
2. With a test light connected to ground, probe
the ignition feed terminal 2 of the injector har-
ness connector for each cylinder that had mis-
fire.
3. Crank the engine.
Does the test light illuminate?–Go to Step 17Go to Step 19
16Replace any malfunctioning fuel injectors.
Is the repair complete?Go to Step 27–
17Check the affected fuel injector driver circuit at termi-
nals 59, 89, 90, and 60 for an open, short, or short
to voltage.
Is a problem found?–Go to Step 18Go to Step 24
18Repair the open or the shorted fuel injector driver cir-
cuit.
Is the repair complete?–Go to Step 27–

1F – 196IENGINE CONTROLS
DAEWOO V–121 BL4
DTC P0327 – Knock Sensor Circuit Fault (1.4L DOHC)
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. Start the engine.
2. Install a scan tool.
3. Clear the Diagnostic Trouble Codes (DTCs).
4. Operate the vehicle within the Freeze Frame
conditions and conditions for setting the DTC
as noted.
Does the Malfunction Indicator (MIL) illuminate?–Go to Step 4Go to Step 3
31. Turn the ignition switch ON, with the engine
OFF.
2. Review the Freeze Frame data and note the
parameters.
3. Operate the vehicle within the Freeze Frame
conditions and conditions for Setting The DTC
as noted.
Does the Malfunction Indicator (MIL) illuminate?–Go to Step 4Go to Step 12
4Listen to the engine while raising and lowering the
engine speed.
Is a knock or audible noise present?–Go to Step 5Go to Step 6
5Repair the mechanical engine problem or a loose
bracket or component.
Is the repair complete?–Go to Step 12–
61. Turn the ignition switch to lock.
2. Disconnect the engine control module(ECM).
3. With a digital voltmeter (DVM) connected to
ground, measure the resistance of the knock
sensor through the knock sensor signal circuit,
terminal 42.
Is the measured value within the specified value?90–100KWGo to Step 7Go to Step 9
7Check for a poor connection at the ECM connector,
knock sensor (KS) signal circuit and repair as neces-
sary.
Is a repair necessary?–Go to Step 12Go to Step 8
8Replace the engine control module(ECM).
Is the replacement complete?–Go to Step 12Go to Step 10
9Check the KS electrical connector for a poor connec-
tion and repair an necessary.
Is a repair necessary?–Go to Step 12Go to Step 10
10Check the KS signal circuit for an open or a low volt-
age or voltage and repair as necessary.
Is a repair necessary?–Go to Step 12Go to Step 11
11Replace the KS.
Is the replacement complete?–Go to Step 12–

ENGINE CONTROLS 1F – 199
DAEWOO V–121 BL4
DTC P0327 – Knock Sensor Circuit Fault (1.6L DOHC)
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. Start the engine.
2. Install a scan tool.
3. Clear the Diagnostic Trouble Codes (DTCs).
4. Operate the vehicle within the Freeze Frame
conditions and conditions for setting the DTC
as noted.
Does the Malfunction Indicator (MIL) illuminate?–Go to Step 4Go to Step 3
31. Turn the ignition switch ON, with the engine
OFF.
2. Review the Freeze Frame data and note the
parameters.
3. Operate the vehicle within the Freeze Frame
conditions and conditions for Setting The DTC
as noted.
Does the Malfunction Indicator (MIL) illuminate?–Go to Step 4Go to Step 12
4Listen to the engine while raising and lowering the
engine speed.
Is a knock or audible noise present?–Go to Step 5Go to Step 6
5Repair the mechanical engine problem or a loose
bracket or component.
Is the repair complete?–Go to Step 12–
61. Turn the ignition switch to lock.
2. Disconnect the engine control module(ECM).
3. With a digital voltmeter (DVM) connected to
ground, measure the resistance of the knock
sensor through the knock sensor signal circuit,
terminal 42.
Is the measured value within the specified value?90–100KWGo to Step 7Go to Step 9
7Check for a poor connection at the ECM connector,
knock sensor (KS) signal circuit and repair as neces-
sary.
Is a repair necessary?–Go to Step 12Go to Step 8
8Replace the engine control module(ECM).
Is the replacement complete?–Go to Step 12Go to Step 10
9Check the KS electrical connector for a poor connec-
tion and repair an necessary.
Is a repair necessary?–Go to Step 12Go to Step 10
10Check the KS signal circuit for an open or a low volt-
age or voltage and repair as necessary.
Is a repair necessary?–Go to Step 12Go to Step 11
11Replace the KS.
Is the replacement complete?–Go to Step 12–