| DTC Code | DTC Name |
|---|---|
| P0300 | Random / Multiple Cylinder Misfire Detected |
| P0301 | Cylinder 1 Misfire Detected |
| P0302 | Cylinder 2 Misfire Detected |
| P0303 | Cylinder 3 Misfire Detected |
| P0304 | Cylinder 4 Misfire Detected |
DESCRIPTION
When the engine misfires, high concentrations of hydrocarbon (HC) enter the exhaust gas. High HC concentration levels can cause an increase in exhaust emission levels. Extremely high concentrations of HC can also cause increases in the three-way catalytic converter temperature, which may cause damage to the three-way catalytic converter. To prevent this increase in emissions and to limit the possibility of thermal damage, the ECM monitors the misfire rate. When the temperature of the three-way catalytic converter reaches the point of thermal degradation, the ECM blinks the MIL. To monitor misfires, the ECM uses both the camshaft position sensor and the crankshaft position sensor. The camshaft position sensor is used to identify any misfiring cylinders and the crankshaft position sensor is used to measure variations in the crankshaft rotation speed. Misfires are counted when the crankshaft rotation speed variations exceed predetermined thresholds. If the misfire count exceeds the threshold levels, and could cause emission control system performance deterioration, the ECM illuminates the MIL and sets a DTC.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P0300 | Simultaneous misfiring of several cylinders occurs and one of the following conditions below is detected (2 trip detection logic):
|
|
| P0301 P0302 P0303 P0304 |
Misfiring of a specific cylinder occurs and one of the following conditions below is detected (2 trip detection logic):
|
When multiple DTCs for misfiring cylinders are stored, but DTC P0300 is not stored, it indicates that misfires have been detected in different cylinders at different times. DTC P0300 is only stored when several misfiring cylinders are detected at the same time.
MONITOR DESCRIPTION
The ECM illuminates the MIL and sets a DTC when the following conditions, which could cause emission control system performance deterioration, is detected (2 trip detection logic).
An excessive misfiring rate (approximately 20 to 50 misfires per 1000 crankshaft revolutions) occurs a total of 4 times.
The ECM flashes the MIL and sets a DTC when either one of the following conditions, which could cause the three-way catalytic converter damage, is detected (2 trip detection logic).
If a catalyst damage misfire occurs, the monitor informs the driver by blinking the MIL (1 trip).
A sufficient amount of misfire to damage the catalyst occurring within 200 crankshaft revolutions is detected 3 times.
MONITOR STRATEGY
| Required Sensors/Components (Main) | Crankshaft position sensor Camshaft position sensor |
| Required Sensors/Components (Related) | Engine coolant temperature sensor Intake air temperature sensor Mass air flow meter sub-assembly |
| Frequency of Operation | Continuous |
TYPICAL ENABLING CONDITIONS
| Either of the following conditions (a) or (b) is met | - |
| (a) Engine coolant temperature at engine start | Higher than -7°C (19°F) |
| (b) Engine coolant temperature | Higher than 20°C (68°F) |
| Duration | Crankshaft 1000 revolutions x 4 |
| Duration | Crankshaft 200 revolutions x 3 |
CONFIRMATION DRIVING PATTERN
Connect the intelligent tester to the DLC3.
Turn the power switch on (IG).
Turn the tester on.
Record the DTC(s) and freeze frame data.
Switch the ECM from normal mode to check mode (Click here).
Clear the DTCs (even if no DTCs are stored, perform the clear DTC operation).
Put the engine in inspection mode (maintenance mode) (Click here).
Read the misfire counts of each cylinder, Cylinder #1 Misfire Count to Cylinder #4 Misfire Count, with the engine idling. If any misfire count is displayed, skip the following confirmation driving pattern.
Drive the vehicle several times with the conditions, such as engine speed and engine load, as shown in Misfire RPM and Misfire Load in the freeze frame data.
In order to store misfire DTCs, it is necessary to operate the vehicle for the period of time shown in the table below with the engine speed and engine load the same as Misfire RPM and Misfire Load in the freeze frame data.
| Engine Speed | Duration |
|---|---|
| Idling | 4 minutes or more |
| 1000 | 4 minutes and 30 seconds or more |
| 2000 | 2 minutes and 30 seconds or more |
| 3000 | 1 minute and 30 seconds or more |
Check whether misfires have occurred by checking DTCs and freeze frame data.
Do not turn the power switch off until the stored DTCs and freeze frame data have been recorded. When the ECM returns to normal mode (default), the stored DTCs, freeze frame data and other data will be cleared.
Record the DTCs, freeze frame data and misfire counts.
Turn the power switch off and wait for at least 30 seconds.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC operation).
WIRING DIAGRAM
Fuel injector circuit: Refer to Fuel Injector Circuit (Click here).
Mass air flow meter sub-assembly circuit: Refer to DTC P0102 (Click here).
INSPECTION PROCEDURE
If any DTCs other than misfire DTCs are output, troubleshoot those DTCs first.
Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
If the misfire does not recur when the vehicle is brought to the workshop, reproduce the conditions stored in the ECM as freeze frame data.
If the misfire still cannot be reproduced even though the conditions stored in the ECM as freeze frame data have been reproduced, one of the following factors may be a cause of the problem:
The fuel level is low.
Improper fuel is being used.
The spark plugs are dirty.
After finishing repairs, check that no misfires occur in each cylinder (Cylinder No. 1, No. 2, No. 3 and No. 4).
Be sure to confirm that no misfiring cylinder DTCs are stored again by conducting the confirmation driving pattern after the repairs.
When one of Short FT #1or Long FT #1 in the freeze frame data is outside the range of +/-20%, the air fuel ratio may be Rich (-20% or less) or Lean (+20% or more).
When the Coolant Temp in the freeze frame data is less than 75°C (167°F), the misfire has occurred only while warming up the engine.
An extremely imbalanced drive wheel which causes body vibration may cause misfire DTCs to be stored.
PROCEDURE
CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO MISFIRE DTCS)
Connect the intelligent tester to the DLC3.
Turn the power switch on (IG).
Turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / DTC.
Read the DTCs.
| Result | Proceed to |
|---|---|
| DTC P0300, P0301, P0302, P0303 and/or P0304 are output | A |
| DTC P0300, P0301, P0302, P0303 and/or P0304 and other DTCs are output | B |
If any DTCs other than P0300, P0301, P0302, P0303 and/or P0304 are output, troubleshoot those DTCs first.
CHECK PCV HOSE CONNECTIONS
Check the PCV hose connections (Click here).
| OK |
|---|
| PCV hose is connected correctly and is not damaged. |
READ VALUE USING INTELLIGENT TESTER (MISFIRE RPM AND MISFIRE LOAD)
Connect the intelligent tester to the DLC3.
Turn the power switch on (IG).
Turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Misfire RPM and Misfire Load.
Read and note the Misfire RPM and Misfire Load values.
The Misfire RPM and Misfire Load values indicate the vehicle conditions under which the misfire occurred.
READ VALUE USING INTELLIGENT TESTER (CYLINDER #1 (TO #4) MISFIRE COUNT)
Connect the intelligent tester to the DLC3.
Turn the power switch on (IG).
Turn the tester on.
Clear the DTCs (Click here).
Put the engine in inspection mode (maintenance mode) (Click here).
Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Cylinder #1 (to #4) Misfire Count.
Start the engine and allow the engine to idle.
Read each value for Cylinder #1 Misfire Count to Cylinder #4 Misfire Count displayed on the tester. If no misfire counts occur in any cylinders, perform steps (i) and (j) and then check the misfire counts again.
Drive the vehicle with the Misfire RPM and Misfire Load noted in the "Read Value Using Intelligent Tester (Misfire Rpm And Misfire Load)" procedures above.
Read the Cylinder #1 Misfire Count to Cylinder #4 Misfire Count or DTCs displayed on the tester.
| Result | Proceed to |
|---|---|
| Most misfires occur in only 1 or 2 cylinders | A |
| 3 cylinders or more have equal misfire counts | B |
If it is difficult to reproduce misfires for each cylinder, check the Data List item called Misfire Margin. Try to find vehicle driving conditions that lower the Misfire Margin value. Values above 30% are considered normal.
If the freeze frame data record of the engine coolant temperature is below 75°C (167°F), it may only be possible to detect the misfire when the engine is cold.
INSPECT SPARK PLUG
Inspect the spark plug of the misfiring cylinder (Click here).
CHECK FOR SPARKS AND IGNITION
Perform a spark test (Click here).
Always disconnect all fuel injector assembly connectors.
Do not crank the engine for more than 2 seconds.
| OK |
|---|
| Spark jumps across electrode gap. |
CHECK CYLINDER COMPRESSION PRESSURE OF MISFIRING CYLINDER
Measure the cylinder compression pressure of the misfiring cylinder (Click here).
CHECK FUEL INJECTOR ASSEMBLY (POWER SOURCE VOLTAGE)
Disconnect the fuel injector assembly connectors.
Turn the power switch on (IG).
Measure the voltage according to the value(s) in the table below.
| Standard Voltage | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
| *a | Front view of wire harness connector (to Fuel Injector Assembly) |
CHECK HARNESS AND CONNECTOR (FUEL INJECTOR ASSEMBLY - ECM)
Disconnect the fuel injector assembly connectors.
Disconnect the ECM connector.
Measure the resistance according to the value(s) in the table below.
| Standard Resistance | |||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
CHECK FUEL INJECTOR ASSEMBLY OF MISFIRING CYLINDER
Check the fuel injector assembly injection (whether fuel volume is high or low, and whether injection pattern is poor) (Click here).
CHECK INTAKE SYSTEM
Check the intake system for vacuum leaks (Click here).
| OK |
|---|
| No leaks in intake system. |
CHECK FUEL PRESSURE
Check the fuel pressure (Click here).
READ VALUE USING INTELLIGENT TESTER (COOLANT TEMP)
Connect the intelligent tester to the DLC3.
Turn the power switch on (IG).
Turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
Read the Data List twice, when the engine is both cold and warmed up.
| Tester Display | Condition | Specified Condition |
|---|---|---|
| Coolant Temp | Cold engine | Same as ambient air temperature |
| Warm engine | Between 75 and 100°C (167 and 212°F) |
READ VALUE USING INTELLIGENT TESTER (MAF)
Connect the intelligent tester to the DLC3.
Turn the power switch on (IG).
Turn the tester on.
Put the engine in inspection mode (maintenance mode) (Click here).
Start the engine.
Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / MAF and Coolant Temp.
Allow the engine to idle until Coolant Temp reaches 75°C (167°F) or higher.
Read MAF with the engine speed at 2500 rpm.
| Tester Display | Condition | Specified Condition |
|---|---|---|
| MAF | Shift lever position: P Engine Speed: 2500 rpm |
Between 4.5 gm/sec. and 8.5 gm/sec. |
ADJUST VALVE TIMING
There are no marks on the cylinder head to match-up for the purpose of checking valve timing. Valve timing can only be inspected by lining up the colored plates on the timing chain with the marks on the pulleys. It may be necessary to remove and reinstall the chain to match-up the alignment marks (Click here).
| *a | Top |
| *b | Alignment Mark |
| *c | No. 1 Cylinder at TDC Compression |
CHECK WHETHER DTC OUTPUT RECURS (P0300, P0301, P0302, P0303 OR P0304)
Connect the intelligent tester to the DLC3.
Turn the power switch on (IG).
Turn the tester on.
Clear the DTCs (Click here).
Turn the power switch off and wait for at least 30 seconds.
Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
Input the DTC: P0300, P0301, P0302, P0303 or P0304.
Check the DTC judgment result.
| Result | Proceed to |
|---|---|
| ABNORMAL (DTC P0300, P0301, P0302, P0303 or P0304 is output) |
A |
| NORMAL (DTC is not output) |
B |
PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE EGR STEP POSITION)
Connect the intelligent tester to the DLC3.
Turn the power switch on (IG).
Turn the tester on.
Put the engine in inspection mode (maintenance mode) (See page )Click here.
Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.
The A/C switch and all accessory switches should be off.
Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position / Data List / All Data / Throttle Idle Position and MAP.
Confirm that the Throttle Idle Position is ON and check the MAP value in the Data List while performing the Active Test.
Do not leave the EGR valve open for 10 seconds or more during the Active Test.
Be sure to return the EGR valve to step 0 when the Active Test is completed.
Do not open the EGR valve 30 steps or more during the Active Test.
| OK |
|---|
| MAP change in response to EGR step position when Throttle Idle Position is ON in Data List. |
| Standard | ||||||||
|---|---|---|---|---|---|---|---|---|
|
||||||||
While performing the Active Test, if the increase in the value of MAP is small, the EGR valve assembly may be a malfunctioning.
Even if the EGR valve assembly is malfunctioning, rough idling or an increase in the value of MAP may occur while performing the Active Test. However, the amount that the value of MAP increases will be smaller than normal.
| Result | ||||||
|---|---|---|---|---|---|---|
|
INSPECT EGR VALVE ASSEMBLY
Remove the EGR valve assembly (Click here).
Check if the EGR valve is stuck open.
| OK |
|---|
| EGR valve is tightly closed. |
| Result | Proceed to |
|---|---|
| NG | A |
| OK | B |
CHECK INTAKE SYSTEM
Check the intake system for vacuum leaks (Click here).
| OK |
|---|
| No leaks in intake system. |
CHECK FUEL PRESSURE
Check the fuel pressure (Click here).
READ VALUE USING INTELLIGENT TESTER (COOLANT TEMP)
Connect the intelligent tester to the DLC3.
Turn the power switch on (IG).
Turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
Read the Data List twice, when the engine is both cold and warmed up.
| Tester Display | Condition | Specified Condition |
|---|---|---|
| Coolant Temp | Cold engine | Same as ambient air temperature |
| Warm engine | Between 75 and 100°C (167 and 212°F) |
READ VALUE USING INTELLIGENT TESTER (MAF)
Connect the intelligent tester to the DLC3.
Turn the power switch on (IG).
Turn the tester on.
Put the engine in inspection mode (maintenance mode) (Click here).
Start the engine.
Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / MAF and Coolant Temp.
Allow the engine to idle until Coolant Temp reaches 75°C (167°F) or higher.
Read MAF with the engine speed at 2500 rpm.
| Tester Display | Condition | Specified Condition |
|---|---|---|
| MAF | Shift lever position: P Engine Speed: 2500 rpm |
Between 4.5 gm/sec. and 8.5 gm/sec. |
PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE EGR STEP POSITION)
Connect the intelligent tester to the DLC3.
Turn the power switch on (IG).
Turn the tester on.
Put the engine in inspection mode (maintenance mode) (Click here).
Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.
The A/C switch and all accessory switches should be off.
Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position / Data List / All Data / Throttle Idle Position and MAP.
Confirm that the Throttle Idle Position is ON and check the MAP value in the Data List while performing the Active Test.
Do not leave the EGR valve open for 10 seconds or more during the Active Test.
Be sure to return the EGR valve to step 0 when the Active Test is completed.
Do not open the EGR valve 30 steps or more during the Active Test.
| OK |
|---|
| MAP change in response to EGR step position when Throttle Idle Position is ON in Data List. |
| Standard | ||||||||
|---|---|---|---|---|---|---|---|---|
|
||||||||
While performing the Active Test, if the increase in the value of MAP is small, the EGR valve assembly may be a malfunctioning.
Even if the EGR valve assembly is malfunctioning, rough idling or an increase in the value of MAP may occur while performing the Active Test. However, the amount that the value of MAP increases will be smaller than normal.
| Result | ||||||
|---|---|---|---|---|---|---|
|
INSPECT EGR VALVE ASSEMBLY
Remove the EGR valve assembly (Click here).
Check if the EGR valve is stuck open.
| OK |
|---|
| EGR valve is tightly closed. |
INSPECT SPARK PLUG
Inspect the spark plug of the misfiring cylinder (Click here).
CHECK FOR SPARKS AND IGNITION
Perform a spark test (Click here).
Always disconnect all fuel injector assembly connectors.
Do not crank the engine for more than 2 seconds.
| OK |
|---|
| Spark jumps across electrode gap. |
CHECK CYLINDER COMPRESSION PRESSURE OF MISFIRING CYLINDER
Measure the cylinder compression pressure of the misfiring cylinder (Click here).
CHECK FUEL INJECTOR ASSEMBLY (POWER SOURCE VOLTAGE)
Disconnect the fuel injector assembly connectors.
Turn the power switch on (IG).
Measure the voltage according to the value(s) in the table below.
| Standard Voltage | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
| *a | Front view of wire harness connector (to Fuel Injector Assembly) |
CHECK HARNESS AND CONNECTOR (FUEL INJECTOR ASSEMBLY - ECM)
Disconnect the fuel injector assembly connectors.
Disconnect the ECM connector.
Measure the resistance according to the value(s) in the table below.
| Standard Resistance | |||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
CHECK FUEL INJECTOR ASSEMBLY OF MISFIRING CYLINDER
Check the fuel injector assembly injection (whether fuel volume is high or low, and whether injection pattern is poor) (Click here).
ADJUST VALVE TIMING
There are no marks on the cylinder head to match-up for the purpose of checking valve timing. Valve timing can only be inspected by lining up the colored plates on the timing chain with the marks on the pulleys. It may be necessary to remove and reinstall the chain to match-up the alignment marks (Click here).
| *a | Top |
| *b | Alignment Mark |
| *c | No. 1 Cylinder at TDC Compression |
CHECK WHETHER DTC OUTPUT RECURS (DTC P0300, P0301, P0302, P0303 OR P0304)
Connect the intelligent tester to the DLC3.
Turn the power switch on (IG).
Turn the tester on.
Clear the DTCs (Click here).
Turn the power switch off and wait for at least 30 seconds.
Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.
Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
Input the DTC: P0300, P0301, P0302, P0303 or P0304.
Check the DTC judgment result.
| Result | Proceed to |
|---|---|
| ABNORMAL (DTC P0300, P0301, P0302, P0303 or P0304 is output) |
A |
| NORMAL (DTC is not output) |
B |
CHECK HARNESS AND CONNECTOR
Check the connection and terminal contact pressure of the connectors and wire harness between the mass air flow meter sub-assembly and ECM (Click here).
Repair any problems.
CHECK DTC OUTPUT RECURS (DTC P0300, P0301, P0302, P0303 OR P0304)
Connect the intelligent tester to the DLC3.
Turn the power switch on (IG).
Turn the tester on.
Clear the DTCs (Click here).
Turn the power switch off and wait for at least 30 seconds.
Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
Input the DTC: P0300, P0301, P0302, P0303 or P0304.
Check the DTC judgment result.
| Result | Proceed to |
|---|---|
| ABNORMAL (DTC P0300, P0301, P0302, P0303 or P0304 is output) |
A |
| NORMAL (DTC is not output) |
B |
CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM)
Disconnect the mass air flow meter sub-assembly connector.
Disconnect the ECM connector.
Measure the resistance according to the value(s) in the table below.
| Standard Resistance | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
REPLACE MASS AIR FLOW METER SUB-ASSEMBLY
Replace the mass air flow meter sub-assembly (Click here).
If the result of the inspection performed in steps 14 and 22 indicated no problem, proceed to the next step without replacing the mass air flow meter sub-assembly.
CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED
Connect the intelligent tester to the DLC3.
Turn the power switch on (IG).
Turn the tester on.
Clear the DTCs (Click here).
Turn the power switch off and wait for at least 30 seconds.
Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.
Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
Input the DTC: P0300, P0301, P0302, P0303 or P0304.
Check the DTC judgment result.
| Result | Proceed to |
|---|---|
| ABNORMAL (DTC P0300, P0301, P0302, P0303 or P0304 is output) |
A |
| NORMAL (DTC is not output) |
B |
CHANGE TO KNOWN GOOD SPARK PLUG AND CHECK SPARK OF MISFIRING CYLINDER
Change the installed spark plug to a spark plug that functions normally.
Perform a spark test (Click here).
Always disconnect all fuel injector assembly connectors.
Do not crank the engine for more than 2 seconds.
| OK |
|---|
| Sparks jump across electrode gap. |
CHANGE TO KNOWN GOOD IGNITION COIL ASSEMBLY AND CHECK SPARK OF MISFIRING CYLINDER
Change the ignition coil assembly to an ignition coil assembly that functions normally.
Perform a spark test (Click here).
Always disconnect all fuel injector assembly connectors.
Do not crank the engine for more than 2 seconds.
| OK |
|---|
| Sparks jump across electrode gap. |
CHECK FUEL LINE
Check the fuel lines for leaks or blockage.
GO TO DTC CHARTClick here
REPAIR OR REPLACE PCV HOSE
REPLACE SPARK PLUGClick here
CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION
GO TO FUEL INJECTOR CIRCUITClick here
REPAIR OR REPLACE HARNESS OR CONNECTOR
REPLACE FUEL INJECTOR ASSEMBLYClick here
REPAIR OR REPLACE INTAKE SYSTEM
REPLACE ENGINE COOLANT TEMPERATURE SENSORClick here
END
REPLACE EGR VALVE ASSEMBLYClick here
REPAIR OR REPLACE HARNESS OR CONNECTOR
REPLACE SPARK PLUGClick here
REPLACE ECMClick here
REPLACE IGNITION COIL ASSEMBLYClick here
REPAIR OR REPLACE FUEL LINE
REPLACE FUEL PUMPClick here