2004 DAEWOO LACETTI fuel type

ENGINE CONTROLS 1F – 233
DAEWOO V–121 BL4
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
Although this DTC is considered a type. A diagnostic, it
acts like a type B diagnostic under certain conditions.
Whenever this diagnostic reports the system has passed,
or if the battery is disconnected, the diagnostic must fail
twice before setting a DTC. The initial failure is not re-ported to the diagnostic executive or displayed on a scan
tool. A passing system always reports to the diagnostic
executive immediately.
Check for the following conditions :
S Missing or damaged fuel cap.
S Missing or damaged O–rings at fuel vapor and
EVAP purge line canister fittings.
S Cracked or punctured EVAP canister.
S Damaged source vacuum line, EVAP purge line,
EVAP vent hose or fuel tank vapor line.
S Poor 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.
S Damaged harness. Inspect the wiring harness to
the EVAP vent solenoid, EVAP canister purge
valve, and the fuel tank pressure sensor for an in-
termittent open or short circuit.
S Kinked, pinched or plugged vacuum source, EVAP
purge, or fuel tank vapor line. Verify that the lines
are not restricted.
DTC P0444 – EVAP Purge Control Circuit No Signal
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. Disconnect the evaporative emission (EVAP)
canister purge valve connector.
2. Connect a test light between the EVAP canister
purge valve connector terminal 1 and battery
positive.
Is the test light ON?–Go to Step 3Go to Step 5
31. Disconnect the ECM connector.
2. Connect a test light between the ECM connec-
tor terminal 65 and ground.
Is the test light ON?–Go to Step 4Go to Step 6
41. Repair the line break in the wire between the
EVAP canister purge valve connector 2 and the
ECM connector terminal 65.
2. Clear any Diagnostic Trouble Codes (DTCs)
from the ECM.
3. Perform the diagnostic system check.
Is the repair complete?–System OK–

1F – 236IENGINE CONTROLS
DAEWOO V–121 BL4
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
Although this DTC is considered a type. A diagnostic, it
acts like a type B diagnostic under certain conditions.
Whenever this diagnostic reports the system has passed,
or if the battery is disconnected, the diagnostic must fail
twice before setting a DTC. The initial failure is not re-ported to the diagnostic executive or displayed on a scan
tool. A passing system always reports to the diagnostic
executive immediately.
Check for the following conditions :
S Missing or damaged fuel cap.
S Missing or damaged O–rings at fuel vapor and
EVAP purge line canister fittings.
S Cracked or punctured EVAP canister.
S Damaged source vacuum line, EVAP purge line,
EVAP vent hose or fuel tank vapor line.
S Poor 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.
S Damaged harness. Inspect the wiring harness to
the EVAP vent solenoid, EVAP canister purge
valve, and the fuel tank pressure sensor for an in-
termittent open or short circuit.
S Kinked, pinched or plugged vacuum source, EVAP
purge, or fuel tank vapor line. Verify that the lines
are not restricted.
DTC P0445 – EVAP Purge Control Circuit Fault
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. Disconnect the evaporative emission (EVAP)
canister purge valve connector.
2. Measure the resistance of the EVAP canister
purge valve connector.
Does the resistance measure near within the value
specified?30WGo to Step 3Go to Step 9
3Connect a test light between EVAP canister purge
valve connector terminal 2 and ground.
Is the test light ON?–Go to Step 4Go to Step 6
41. Disconnect the ECM connector.
2. Connect a test light between the ECM connec-
tor terminal 65 and ground.
Is the test light ON?–Go to Step 5Go to Step 7
51. Repair the high voltage or ground in the wire
between the EVAP canister purge valve con-
nector terminal 2 and the ECM connector ter-
minal 65.
2. Clear any Diagnostic Trouble Codes (DTCs)
from the ECM.
3. Perform the diagnostic system check.
Is the repair complete?–System OK–

1F – 344IENGINE CONTROLS
DAEWOO V–121 BL4
TROUBLE CODE DIAGNOSIS (1.8L DOHC)
CLEARING TROUBLE CODES
Notice : To prevent Engine Control Module (ECM) dam-
age, the key must be OFF when disconnecting or recon-
necting the power to the ECM (for example battery cable,
ECM pigtail connector, ECM fuse, jumper cables, etc.).
When the ECM sets a Diagnostic Trouble Code (DTC), the
Malfunction Indicator Lamp (MIL) lamp will be turned on
only for type A, B and E but a DTC will be stored in the
ECM’s memory for all types of DTC. If the problem is inter-mittent, the MIL will go out after 10 seconds if the fault is
no longer present. The DTC will stay in the ECM’s memory
until cleared by scan tool. Removing battery voltage for 10
seconds will clear some stored DTCs.
DTCs should be cleared after repairs have been com-
pleted. Some diagnostic tables will tell you to clear the
codes before using the chart. This allows the ECM to set
the DTC while going through the chart, which will help to
find the cause of the problem more quickly.
DIAGNOSTIC TROUBLE CODES (1.8L DOHC)
DTCDescriptionTypeIlluminate MIL
P0106Manifold Absolute Pressure RationalityEYe s
P0107Manifold Absolute Pressure Low VoltageAYe s
P0108Manifold Absolute Pressure High VoltageAYe s
P0112Intake Air Temperature Low VoltageEYe s
P0113Intake Air Temperature High VoltageEYe s
P0117Engine Coolant Temperature Low VoltageAYe s
P0118Engine Coolant Temperature High VoltageAYe s
P0122Throttle Position Sensor Low VoltageAYe s
P0123Throttle Position Sensor High VoltageAYe s
P0131Front Heated Oxygen Sensor (HO2S1) Low VoltageAYe s
P0132Front Heated Oxygen Sensor (HO2S1) High VoltageAYe s
P0133Front Heated Oxygen Sensor (HO2S1) Slow ResponseEYe s
P0134Front Heated Oxygen Sensor (HO2S1) No Activity or OpenAYe s
P0135Front Heated Oxygen Sensor (HO2S1) Heater Circuit Not FunctioningEYe s
P0137Rear Heated Oxygen Sensor (HO2S2) Low VoltageEYe s
P0138Rear Heated Oxygen Sensor (HO2S2) High VoltageEYe s
P0140Rear Heated Oxygen Sensor (HO2S2) No Activity or OpenEYe s
P0141Rear Heated Oxygen Sensor (HO2S2) Heater Circuit Not FunctioningEYe s
P0171Fuel Trim System Too LeanBYe s
P0172Fuel Trim System Too RichBYe s
P0201Injector 1 Circuit FaultAYe s
P0202Injector 2 Circuit FaultAYe s
P0203Injector 3 Circuit FaultAYe s
P0204Injector 4 Circuit FaultAYe s
P0300Multiple Cylinder Misfire DetectedBYe s
P0301Cylinder 1 MisfireAYe s
P0302Cylinder 2 MisfireAYe s
P0303Cylinder 3 MisfireAYe s
P0304Cylinder 4 MisfireAYe s
P0317Rough Road Sensor Source Not DetectedCnlNo
P0325Knock Sensor Internal MalfunctionCnlNo

ENGINE CONTROLS 1F – 345
DAEWOO V–121 BL4
DTCIlluminate MIL Type Description
P0327Knock Sensor Circuit FaultCnlNo
P033658X Crank Position Sensor Extra/Missing PulsesEYe s
P033758X Crank Position Sensor No SignalAYe s
P0341Camshaft Position Sensor RationalityEYe s
P0342Camshaft Position Sensor No SignalAYe s
P0351Ignition Control Circuit A Fault (Cylinder 1 and 4)AYe s
P0352Ignition Control Circuit B Fault (Cylinder 2 and 3)AYe s
P0401Exhaust Gas Recirculation Insufficient FlowCnlNo
P0402Exhaust Gas Recirculation Excessive FlowEYe s
P0404Exhaust Gas Recirculation Open Valve Position ErrorEYe s
P0405Exhaust Gas Recirculation Pintle Position Low VoltageEYe s
P0406Exhaust Gas Recirculation Pintle Position High VoltageEYe s
P0420Catalyst Oxygen Sensor Low EfficiencyAYe s
P0443Evaporative Emission System Purge Solenoid Control CircuitEYe s
P0461Fuel Level StuckCnlNo
P0462Fuel Level Low VoltageCnlNo
P0463Fuel Level High VoltageCnlNo
P0502Vehicle Speed Sensor No Signal (Engine Side)EYe s
P0506Idle Speed rpm Lower Than Desired Idle SpeedEYe s
P0507Idle Speed rpm Higher Than Desired Idle SpeedEYe s
P0532A/C Pressure Sensor Low VoltageCnlNo
P0533A/C Pressure Sensor High VoltageCnlNo
P0562System Voltage Too Low (Engine Side)CnlNo
P0563System Voltage Too High (Engine Side)CnlNo
P0601ECM Checksum Error (Engine Side)AYe s
P0602ECM Reprogram ErrorAYe s
P0607Lower Power Counter ErrorCnlNo
P0700Transaxle Control Module MalfunctionAYe s
P1106Manifold Absolute Pressure Intermittent High VoltageCnlNo
P1107Manifold Absolute Pressure Intermittent Low VoltageCnlNo
P 1111Intake Air Temperature Intermittent High VoltageCnlNo
P1112Intake Air Temperature Intermittent Low VoltageCnlNo
P1114Engine Coolant Temperature Intermittent Low VoltageCnlNo
P1115Engine Coolant Temperature Intermittent High VoltageCnlNo
P1121Throttle Position Sensor Intermittent High VoltageCnlNo
P1122Throttle Position Sensor Intermittent Low VoltageCnlNo
P1133Front Heated Oxygen Sensor (HO2S1) Too Few TransitionsEYe s
P1134Front Heated Oxygen Sensor (HO2S1) Transition RatioEYe s
P1167Front Heated Oxygen Sensor (HO2S1) Rich in Decel Fuel Cut–off (DFCO)AYe s
P1171Fuel Trim System Lean During Power EnrichmentBYe s
P133658X Crank Position Tooth Error Not LearnedAYe s
P1391G Sensor Rough Road RationalityCnlNo

ENGINE CONTROLS 1F – 421
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0300
MULTIPLE CYLINDER MISFIRE DETECTED
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 100 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). Under light misfire condi-
tions, it may also take more than one trip to set a DTC. Se-
vere misfire will flash the MIL, indicating that catalyst
damage is possible.
Conditions for Setting the DTC
S Emission threshold is 3%.
S 20 engine cycles have occurred since cranking has
started.
S A/C compressor clutch has not just engaged or dis-
engaged.
S Engine load and engine speed is in a detectable
region and is at or above zero torque.
S Camshaft Position (CMP) sensor is in synchroniza-
tion.
S Exhaust Gas Recirculation (EGR) flow diagnostic is
not in progress.
S Fuel level is greater than 12% of rated tank capac-
ity.
S Decel Fuel Cutoff (DFCO) not active.
S Throttle position change is less than 3% per 125
ms.
S Vehicle has not encountered an abusive engine
speed of 7000 rpm.
S Crankshaft speed patters are normal.
S Throttle position is less than 3% when vehicle
speed is greater than 10 km/h (6 mph).
S Vehicle voltage is between 11 and 16 volts.
S Engine Coolant Temperature (ECT) is between
–7°C (19°F) and 120°C (248°F).
S There is the correct ratio between Crankshaft Posi-
tion (CKP) sensor pulses and CMP sensor pulses.
S DTCs P0106, P0107, P0108, P0117, P0118,
P0122, P0123, P0336, P0337, P0341, P0342 and
P0502 are not set.
Action Taken When the DTC Sets
S The MIL will illuminate after two consecutive ignition
cycles in which the diagnostic runs with the fault
active.
Or
S The MIL will illuminate immediately and flash if mis-
fire is present.
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.
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
within the freeze frame conditions that the DTC
failed.
S A history DTC will clear after 40 consecutive warm–
up cycles without a fault.
S The 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 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.
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.
3. A visual/physical inspection should include check-
ing the following components:
S The wiring for proper connections, pinches or
cuts.
S The ECM grounds for being clean and tight.
S The vacuum hoses for splits, kinks, and proper
connections as shown on the Vehicle Emission
Information label. Check thoroughly for any type
of leak or restriction.
S For air leaks at the throttle body mounting area
and intake manifold sealing surfaces.
5. When all the accumulators are relatively equal, then
the misfire is being caused by something that af-
fects the entire engine. When they are not then the
misfire is being caused by something that is specif-
ic to two or more cylinders.
6. Whenever the misfire is not present operating the
vehicle may be necessary to duplicate the condi-
tions in the Freeze Frame Data in order to detect
misfire. Depending on the engine load, the condi-
tions may have to be maintained for up to 20 sec-
onds. Whenever the misfire accumulators start to
increment, then misfire is present. A history misfire
counter will store the number of misfires that have
occurred until the DTC is cleared.

1F – 426IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0301
CYLINDER 1 MISFURE
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 100 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). Under light misfire condi-
tions, it may also take more than one trip to set a DTC. Se-
vere misfire will flash the MIL, indicating that catalyst
damage is possible.
Conditions for Setting the DTC
S Emission threshold is 3%.
S 20 engine cycles have occurred since cranking has
started.
S A/C compressor clutch has not just engaged or dis-
engaged.
S Engine load and engine speed is in a detectable
region and is at or above zero torque.
S Camshaft Position (CMP) sensor is in synchroniza-
tion.
S Exhaust Gas Recirculation (EGR) flow diagnostic is
not in progress.
S Fuel level is greater than 12% of rated tank capac-
ity.
S Decel Fuel Cutoff (DFCO) not active.
S Throttle position change is less than 3% per 125
ms.
S Vehicle has not encountered an abusive engine
speed of 7000 rpm.
S Crankshaft speed patters are normal.
S Throttle position is less than 3% when vehicle
speed is greater than 10 km/h (6 mph).
S Vehicle voltage is between 11 and 16 volts.
S Engine Coolant Temperature (ECT) is between
–7°C (19°F) and 120°C (248°F).
S There is the correct ratio between Crankshaft Posi-
tion (CKP) sensor pulses and CMP sensor pulses.
S DTCs P0106, P0107, P0108, P0117, P0118,
P0122, P0123, P0336, P0337, P0341, P0342 and
P0502 are not set.
Action Taken When the DTC Sets
S The MIL will illuminate after two consecutive ignition
cycles in which the diagnostic runs with the fault
active.
Or
S The MIL will illuminate immediately and flash if mis-
fire is present.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.
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
within the freeze frame conditions that the DTC
failed.
S A history DTC will clear after 40 consecutive warm–
up cycles without a fault.
S The 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 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.
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.
3. A visual/physical inspection should include check-
ing the following components:
S The wiring for proper connections, pinches or
cuts.
S The ECM grounds for being clean and tight.
S The vacuum hoses for splits, kinks, and proper
connections as shown on the Vehicle Emission
Information label.
S Check thoroughly for any type of leak or restric-
tion.
S For air leaks at the throttle body mounting area
and intake manifold sealing surfaces.
5. When all the accumulators are relatively equal, then
the misfire is being caused by something that af-
fects the entire engine. When they are not then the
misfire is being caused by something that is specif-
ic to two or more cylinders.
6. Whenever the misfire is not present operating the
vehicle may be necessary to duplicate the condi-
tions in the Freeze Frame Data in order to detect

ENGINE CONTROLS 1F – 431
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0302
CYLINDER 2 MISFIRE
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 100 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). Under light misfire condi-
tions, it may also take more than one trip to set a DTC. Se-
vere misfire will flash the MIL, indicating that catalyst
damage is possible.
Conditions for Setting the DTC
S Emission threshold is 3%.
S 20 engine cycles have occurred since cranking has
started.
S A/C compressor clutch has not just engaged or dis-
engaged.
S Engine load and engine speed is in a detectable
region and is at or above zero torque.
S Camshaft Position (CMP) sensor is in synchroniza-
tion.
S Exhaust Gas Recirculation (EGR) flow diagnostic is
not in progress.
S Fuel level is greater than 12% of rated tank capac-
ity.
S Decel Fuel Cutoff (DFCO) not active.
S Throttle position change is less than 3% per 125
ms.
S Vehicle has not encountered an abusive engine
speed of 7000 rpm.
S Crankshaft speed patters are normal.
S Throttle position is less than 3% when vehicle
speed is greater than 10 km/h (6 mph).
S Vehicle voltage is between 11 and 16 volts.
S Engine Coolant Temperature (ECT) is between
–7°C (19°F) and 120°C (248°F).
S There is the correct ratio between Crankshaft Posi-
tion (CKP) sensor pulses and CMP sensor pulses.
S DTCs P0106, P0107, P0108, P0117, P0118,
P0122, P0123, P0336, P0337, P0341, P0342 and
P0502 are not set.
Action Taken When the DTC Sets
S The MIL will illuminate after two consecutive ignition
cycles in which the diagnostic runs with the fault
active.
Or
S The MIL will illuminate immediately and flash if mis-
fire is present.
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.
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
within the freeze frame conditions that the DTC
failed.
S A history DTC will clear after 40 consecutive warm–
up cycles without a fault.
S The 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 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.
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.
3. A visual/physical inspection should include check-
ing the following components:
S The wiring for proper connections, pinches or
cuts.
S The ECM grounds for being clean and tight.
S The vacuum hoses for splits, kinks, and proper
connections as shown on the Vehicle Emission
Information label. Check thoroughly for any type
of leak or restriction.
S For air leaks at the throttle body mounting area
and intake manifold sealing surfaces.
5. When all the accumulators are relatively equal, then
the misfire is being caused by something that af-
fects the entire engine. When they are not then the
misfire is being caused by something that is specif-
ic to two or more cylinders.
6. Whenever the misfire is not present operating the
vehicle may be necessary to duplicate the condi-
tions in the Freeze Frame Data in order to detect
misfire. Depending on the engine load, the condi-
tions may have to be maintained for up to 20 sec-
onds. Whenever the misfire accumulators start to
increment, then misfire is present. A history misfire
counter will store the number of misfires that have
occurred until the DTC is cleared.

1F – 436IENGINE CONTROLS
DAEWOO V–121 BL4
DIAGNOSTIC TROUBLE CODE (DTC) P0303
CYLINDER 3 MISFIRE
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 100 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). Under light misfire condi-
tions, it may also take more than one trip to set a DTC. Se-
vere misfire will flash the MIL, indicating that catalyst
damage is possible.
Conditions for Setting the DTC
S Emission threshold is 3%.
S 20 engine cycles have occurred since cranking has
started.
S A/C compressor clutch has not just engaged or dis-
engaged.
S Engine load and engine speed is in a detectable
region and is at or above zero torque.
S Camshaft Position (CMP) sensor is in synchroniza-
tion.
S Exhaust Gas Recirculation (EGR) flow diagnostic is
not in progress.
S Fuel level is greater than 12% of rated tank capac-
ity.
S Decel Fuel Cutoff (DFCO) not active.
S Throttle position change is less than 3% per 125
ms.
S Vehicle has not encountered an abusive engine
speed of 7000 rpm.
S Crankshaft speed patters are normal.
S Throttle position is less than 3% when vehicle
speed is greater than 10 km/h (6 mph).
S Vehicle voltage is between 11 and 16 volts.
S Engine Coolant Temperature (ECT) is between
–7°C (19°F) and 120°C (248°F).
S There is the correct ratio between Crankshaft Posi-
tion (CKP) sensor pulses and CMP sensor pulses.
S DTCs P0106, P0107, P0108, P0117, P0118,
P0122, P0123, P0336, P0337, P0341, P0342 and
P0502 are not set.
Action Taken When the DTC Sets
S The MIL will illuminate after two consecutive ignition
cycles in which the diagnostic runs with the fault
active.
Or
S The MIL will illuminate immediately and flash if mis-
fire is present.
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.
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
within the freeze frame conditions that the DTC
failed.
S A history DTC will clear after 40 consecutive warm–
up cycles without a fault.
S The 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 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.
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.
3. A visual/physical inspection should include check-
ing the following components:
S The wiring for proper connections, pinches or
cuts.
S The ECM grounds for being clean and tight.
S The vacuum hoses for splits, kinks, and proper
connections as shown on the Vehicle Emission
Information label. Check thoroughly for any type
of leak or restriction.
S For air leaks at the throttle body mounting area
and intake manifold sealing surfaces.
5. When all the accumulators are relatively equal, then
the misfire is being caused by something that af-
fects the entire engine. When they are not then the
misfire is being caused by something that is specif-
ic to two or more cylinders.
6. Whenever the misfire is not present operating the
vehicle may be necessary to duplicate the condi-
tions in the Freeze Frame Data in order to detect
misfire. Depending on the engine load, the condi-
tions may have to be maintained for up to 20 sec-
onds. Whenever the misfire accumulators start to
increment, then misfire is present. A history misfire
counter will store the number of misfires that have
occurred until the DTC is cleared.