1F – 182IENGINE CONTROLS
DAEWOO V–121 BL4
DTC P0268 – Injector 3 High 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 P0268 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 P0268 reset?–Go to Step 5Go to
”Diagnostic
Aids”
51. Turn the ignition switch to LOCK.
2. Check for an open or short to battery voltage in
the wire between the injector 3 connector ter-
minal 2 and ECM connector terminal 60.
Is the problem found?–Go to Step 7Go to Step 6
61. Turn the ignition switch to LOCK.
2. Check for short to battery voltage in the wire
between the injector 3 connector terminal 1.
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 P0268 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 – 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.
1F – 186IENGINE CONTROLS
DAEWOO V–121 BL4
DTC P0271 – Injector 4 High 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 P0271 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 P0271 reset?–Go to Step 5Go to
”Diagnostic
Aids”
51. Turn the ignition switch to LOCK.
2. Check for an open or short to battery voltage in
the wire between the injector 3 connector ter-
minal 4 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 battery voltage in the wire
between the injector 4 connector terminal 1.
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 P0271 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
1F – 188IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0300
MULTIPLE CYLINDER MISFIRE (CATALYST DAMAGE)
System Description
The Engine Control Module (ECM) monitors the crank-
shaft and camshaft positions to detect if the engine is mis-
firing. The ECM looks for a quick drop in crankshaft speed.
This test is executed in blocks of 200 engine revolution
tests. It may take between one to several tests to store a
Diagnostic Trouble Code (DTC), the Malfunction Indicator
Lamp (MIL). Severe misfire will flash the MIL, indicating
that catalyst damage is possible.
Conditions for Setting the DTC
S The engine speed is less than 4,500 rpm.
S The fuel tank level is greater than 20%.
S No anti–jerk correction.
S No rough road detection.
S No crankshaft oscillation detection.
S DTCs P0107, P0108, P0122, P0123, P0341,
P0342, P0336 and P0337 are not set.
Action Taken When the DTC SetsS The malfunction Indicator Lamp (MIL) will blinking.
S The ECM will record operating conditions at the
time the diagnostic fails. The 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 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 intermittent can also be the result of a defective reluctor
wheel. Remove the CKP sensor and inspect the reluctor
wheel through the sensor mount hole. Check for porosity
and the condition of wheel. If the DTC is intermittent refer
to ”Symptoms Diagnosis” in this section.
DTC P0300 – Multiple Cylinder Misfire(Catalyst Damage)
StepActionValue(s)YesNo
1Perform an Euro 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, with the engine OFF.
3. Request Diagnostic Trouble Codes (DTCs).
Are DTCs P0261, P0262, P0264, P0265, P0267,
P0268, P0270, P0271 set?–Go to
Applicable DTC
tableGo to Step 3
3Perform a visual/physical inspection.
Make any repairs that are necessary.
Is the repair complete?–Go to Step 27Go to Step 4
4Start the engine and allow it to idle.
Are any Misfire Current counters incrementing?–Go to Step 5Go to Step 6
5Are all counters equal (within a percentage of each
other)?–Go to Step 7Go to Step 11
61. Turn the ignition 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 this DTC
as noted.
Are any Misfire Current counters incrementing?–Go to Step 5Go to
”Diagnostic
Aids”
1F – 192IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0300
MULTIPLE CYLINDER MISFIRE (INCREASE EMISSION)
System Description
The Engine Control Module (ECM) monitors the crank-
shaft and camshaft positions to detect if the engine is mis-
firing. The ECM looks for a quick drop in crankshaft speed.
This test is executed in blocks of 1,000 engine revolution
tests. It may take between one to several tests to store a
Diagnostic Trouble Code (DTC) and illuminate the Mal-
function Indicator Lamp (MIL).
Conditions for Setting the DTC
S The engine speed is less than 4,500 rpm.
S The fuel tank level is greater than 20%.
S No anti–jerk correction.
S No rough road detection.
S No crankshaft oscillation detection.
S DTCs P0107, P0108, P0122, P0123, P0341,
P0342, P0336 and P0337 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 fails. The 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
An intermittent can also be the result of a defective reluctor
wheel. Remove the CKP sensor and inspect the reluctor
wheel through the sensor mount hole. Check for porosity
and the condition of wheel. If the DTC is intermittent refer
to ”Symptoms Diagnosis” in this section.
DTC P0300 – Multiple Cylinder Misfire(Increase Emission)
StepActionValue(s)YesNo
1Perform an Euro 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, with the engine OFF.
3. Request Diagnostic Trouble Codes (DTCs).
Are DTCs P0261, P0262, P0264, P0265, P0267,
P0268, P0270, P0271 set?–Go to
Applicable DTC
tableGo to Step 3
3Perform a visual/physical inspection.
Make any repairs that are necessary.
Is the repair complete?–Go to Step 27Go to Step 4
4Start the engine and allow it to idle.
Are any Misfire Current counters incrementing?–Go to Step 5Go to Step 6
5Are all counters equal (within a percentage of each
other)?–Go to Step 7Go to Step 11
61. Turn the ignition 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 this DTC
as noted.
Are any Misfire Current counters incrementing?–Go to Step 5Go to
”Diagnostic
Aids”
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