| 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 hydrocarbons (HC) enter the exhaust gas. Extremely high hydrocarbon concentration levels can cause an increase in exhaust emission levels. Extremely high concentrations of hydrocarbons 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 count. 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 stores a DTC.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | MIL | Memory |
|---|---|---|---|---|---|
| P0300 | Random / Multiple Cylinder Misfire Detected | Simultaneous misfiring of several cylinders occurs and either of the following conditions is met (2 trip detection logic):
|
|
Comes on/Blinks* *: The MIL flashes when a catalyst-damaging misfire is detected. |
DTC stored |
| P0301 | Cylinder 1 Misfire Detected | Misfiring of the No. 1 cylinder occurs and either of the following conditions is met (2 trip detection logic):
|
|
Comes on/Blinks* *: The MIL flashes when a catalyst-damaging misfire is detected. |
DTC stored |
| P0302 | Cylinder 2 Misfire Detected | Misfiring of the No. 2 cylinder occurs and either of the following conditions is met (2 trip detection logic):
|
|
Comes on/Blinks* *: The MIL flashes when a catalyst-damaging misfire is detected. |
DTC stored |
| P0303 | Cylinder 3 Misfire Detected | Misfiring of the No. 3 cylinder occurs and either of the following conditions is met (2 trip detection logic):
|
|
Comes on/Blinks* *: The MIL flashes when a catalyst-damaging misfire is detected. |
DTC stored |
| P0304 | Cylinder 4 Misfire Detected | Misfiring of the No. 4 cylinder occurs and either of the following conditions is met (2 trip detection logic):
|
|
Comes on/Blinks* *: The MIL flashes when a catalyst-damaging misfire is detected. |
DTC stored |
When DTCs for misfiring cylinders are randomly 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 stores a DTC when the following conditions, which could cause emission deterioration, is detected (2 trip detection logic).
An excessive number of misfires (approximately 80 to 100 misfires per 1000 crankshaft revolutions) occurs a total of 4 times.
The ECM flashes the MIL (immediately detection logic) and stores a DTC (2 trip detection logic) when the following conditions, which could cause damage to the three-way catalytic converter, is detected.
At a normal engine speed, a sufficient amount of misfires 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 Intake air temperature sensor Mass air flow meter sub-assembly |
| Frequency of Operation | Continuous |
TYPICAL ENABLING CONDITIONS
| Intake air temperature | Higher than -10°C (14°F) |
| Either of the following conditions is met | (a) or (b) |
| (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 GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Record the DTC(s) and freeze frame data.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Switch the ECM from normal mode to check mode.
Read the misfire count 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 so that the vehicle conditions displayed in Misfire RPM and Misfire Load of the Data List are the same as the freeze frame data. Perform this step several times.
Tech Tips
In order to store misfire DTCs, it is necessary to operate the vehicle for the period of time shown in the table below, using the Misfire RPM and Misfire Load in the Data List.
| Engine Speed (rpm) | Duration |
|---|---|
| Idling | 8.0 minutes or more |
| 1000 | 4.5 minutes or more |
| 2000 | 2.5 minutes or more |
| 3000 | 1.5 minutes or more |
Check whether misfires have occurred by checking for DTCs and freeze frame data.
Tech Tips
Do not turn the engine switch off until the stored DTC(s) and freeze frame data have been recorded. When the ECM returns to normal mode (default), the stored DTC(s), freeze frame data and other data will be cleared.
Record the DTC(s), freeze frame data and misfire counts.
Turn the engine switch off and wait for at least 30 seconds.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
WIRING DIAGRAM
Refer to DTC P0102 for the mass air flow meter sub-assembly circuit.
Refer to Fuel Injector Circuit.
CAUTION / NOTICE / HINT
Note
Inspect the fuses for circuits related to this system before performing the following procedure.
Tech Tips
Check the "Fuel Cut Elps Time" in the Data List or the Freeze Frame Data.
If the elapsed time is over 0 seconds, then the engine speed is high (engine speed at which fuel cut occurs + 500 rpm).
When this has happened, there is the possibility that the No. 1 valve rocker arm sub-assembly will become loose and a fire could start, so check that the No. 1 valve rocker arm sub-assembly is properly attached.
By clearing the DTCs, "Fuel Cut Elps Time" will be cleared.
If any DTCs other than misfire DTCs are output, troubleshoot those DTCs first.
Read freeze frame data using the GTS. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.
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, the following factors can be considered to be a possible cause of the problem:
There was insufficient fuel in the tank.
Improper fuel was used.
The spark plugs have been contaminated.
The problem requires further diagnosis.
After finishing repairs, check the misfire counts of the cylinders (Cylinder #1 Misfire Count to Cylinder #4 Misfire Count).
Be sure to confirm that no misfiring cylinder DTCs are stored again by conducting the confirmation driving pattern after finishing repairs.
When one of Short FT B1S1 or Long FT B1S1 in the freeze frame data is outside the range of +/-15%, the air fuel ratio may be rich (-15% or less) or lean (15% or higher).
When Coolant Temp in the freeze frame data is less than 75°C (167°F), the misfires have 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 GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
Read the DTCs.
| Result | ||||||
|---|---|---|---|---|---|---|
|
Tech Tips
If any DTCs other than P0300, P0301, P0302, P0303 or P0304 are output, troubleshoot those DTCs first.
| B |
|
GO TO DTC CHART Click here |
| A |
|
CHECK PCV HOSE CONNECTIONS
Check the PCV hose connections.
| OK |
|---|
| PCV valve and hose are correctly connected and are not damaged. |
| Result | |||
|---|---|---|---|
|
| NG |
|
REPAIR OR REPLACE PCV HOSE |
| OK |
|
READ VALUE USING GTS (MISFIRE RPM AND MISFIRE LOAD)
Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Data List / Primary / Misfire RPM and Misfire Load.
| Tester Display |
|---|
| Misfire RPM |
| Misfire Load |
Read and note the Misfire RPM and Misfire Load values.
Tech Tips
The Misfire RPM and Misfire Load values indicate the vehicle conditions under which the misfire occurred.
| Result | ||
|---|---|---|
|
| NEXT |
|
READ VALUE USING GTS (CYLINDER MISFIRE COUNT)
Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Data List / Primary / Cylinder #1 Misfire Count, Cylinder #2 Misfire Count, Cylinder #3 Misfire Count and Cylinder #4 Misfire Count.
| Tester Display |
|---|
| Cylinder #1 Misfire Count |
| Cylinder #2 Misfire Count |
| Cylinder #3 Misfire Count |
| Cylinder #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 GTS. If no misfire counts occur in any cylinders, perform procedure [A] and [B] and then check the misfire counts again.
Drive the vehicle with the Misfire RPM and Misfire Load noted in the read value using GTS (Misfire RPM and Misfire Load) procedures above [A].
Read the Cylinder #1 Misfire Count to Cylinder #4 Misfire Count or DTCs displayed on the GTS [B].
| Result | ||||||
|---|---|---|---|---|---|---|
|
Tech Tips
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), the misfire may be detected only when the engine is cold.
If the freeze frame data record of the Engine Run Time is below 120 seconds, the misfire may be detected immediately after the engine is started.
| B |
|
CHECK INTAKE SYSTEM Click here |
| A |
|
INSPECT SPARK PLUG
Inspect the spark plug of the misfiring cylinder.
| Result | |||
|---|---|---|---|
|
| NG |
|
REPLACE SPARK PLUG Click here |
| OK |
|
CHECK FOR SPARKS (SPARK TEST)
Perform a spark test.
Tech Tips
If the result of the spark test is normal, proceed to the next step.
Perform "Inspection After Repair" after repairing or replacing the ignition system.
| Result | ||
|---|---|---|
|
| NEXT |
|
CHECK CYLINDER COMPRESSION PRESSURE
Measure the cylinder compression pressure of the misfiring cylinder.
Tech Tips
Perform "Inspection After Repair" after repairing or replacing the engine assembly.
| Result | |||
|---|---|---|---|
|
| NG |
|
CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION |
| OK |
|
CHECK TERMINAL VOLTAGE (#10, #20, #30 AND/OR #40)
| *a | Front view of wire harness connector (to ECM) |
Disconnect the ECM connector.
Turn the engine switch on (IG).
Measure the voltage according to the value(s) in the table below.
| Standard Voltage | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
| Result | |||
|---|---|---|---|
|
| NG |
|
CHECK FUEL INJECTOR CIRCUIT Click here |
| OK |
|
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).
| Result | |||
|---|---|---|---|
|
| NG |
|
REPLACE FUEL INJECTOR ASSEMBLY Click here |
| OK |
|
CHECK INTAKE SYSTEM
Check the intake system for vacuum leaks.
| OK |
|---|
| No leaks from intake system. |
Tech Tips
Perform "Inspection After Repair" after repairing or replacing the intake system.
| Result | |||
|---|---|---|---|
|
| NG |
|
REPAIR OR REPLACE INTAKE SYSTEM |
| OK |
|
CHECK FUEL PRESSURE
Check the fuel pressure.
| Result | |||
|---|---|---|---|
|
| NG |
|
GO TO STEP 32 Click here |
| OK |
|
READ VALUE USING GTS (COOLANT TEMP)
| Result | |||
|---|---|---|---|
|
Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Data List / Primary / Coolant Temp.
| Tester Display |
|---|
| Coolant Temp |
Read the Data List twice, when the engine is both cold and warmed up.
| Standard | ||||||||
|---|---|---|---|---|---|---|---|---|
|
Tech Tips
Perform "Inspection After Repair" after replacing the engine coolant temperature sensor.
| Result | |||
|---|---|---|---|
|
| NG |
|
REPLACE ENGINE COOLANT TEMPERATURE SENSOR Click here |
| OK |
|
READ VALUE USING GTS (MAF)
| Result | |||
|---|---|---|---|
|
Connect the GTS to the DLC3.
Start the engine.
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Data List / Primary / MAF, Coolant Temp and Engine Speed.
| Tester Display |
|---|
| Engine Speed |
| MAF |
| Coolant Temp |
Allow the engine to idle until Coolant Temp reaches 75°C (167°F) or higher.
Read MAF with the engine speed at 3000 rpm.
| Standard | ||||||
|---|---|---|---|---|---|---|
|
| Result | |||
|---|---|---|---|
|
| NG |
|
GO TO STEP 27 Click here |
| OK |
|
CHECK ENGINE MECHANICAL SYSTEM
Check for mechanical malfunctions that affect the valve timing, such as a jumped tooth or stretching of the timing chain.
| Result | |||
|---|---|---|---|
|
| NG |
|
REPAIR OR REPLACE MALFUNCTIONING PARTS, COMPONENT AND AREA |
| OK |
|
CHECK WHETHER DTC OUTPUT RECURS (DTC P0300, P0301, P0302, P0303 OR P0304)
Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Clear the DTCs.
Turn the engine switch off and wait for at least 30 seconds.
Turn the engine switch on (IG).
Turn the GTS on.
Start the engine.
Warm up the engine.
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.
| Tester Display |
|---|
| All Readiness |
Input the DTC: P0300, P0301, P0302, P0303 or P0304.
Check the DTC judgment result.
| Result | ||||||
|---|---|---|---|---|---|---|
|
| A |
|
CHECK FOR INTERMITTENT PROBLEMS Click here |
| B |
|
GO TO STEP 27 Click here |
CHECK INTAKE SYSTEM
Check the intake system for vacuum leaks.
| OK |
|---|
| No leaks from intake system. |
Tech Tips
Perform "Inspection After Repair" after repairing or replacing the intake system.
| Result | |||
|---|---|---|---|
|
| NG |
|
REPAIR OR REPLACE INTAKE SYSTEM |
| OK |
|
CHECK FUEL PRESSURE
Check the fuel pressure.
| Result | |||
|---|---|---|---|
|
| NG |
|
CHECK FUEL LINE Click here |
| OK |
|
READ VALUE USING GTS (COOLANT TEMP)
| Result | |||
|---|---|---|---|
|
Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Data List / Primary / Coolant Temp.
| Tester Display |
|---|
| Coolant Temp |
Read the Data List twice, when the engine is both cold and warmed up.
| Standard | ||||||||
|---|---|---|---|---|---|---|---|---|
|
Tech Tips
Perform "Inspection After Repair" after replacing the engine coolant temperature sensor.
| Result | |||
|---|---|---|---|
|
| NG |
|
REPLACE ENGINE COOLANT TEMPERATURE SENSOR Click here |
| OK |
|
READ VALUE USING GTS (MAF)
| Result | |||
|---|---|---|---|
|
Connect the GTS to the DLC3.
Start the engine.
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Data List / Primary / MAF, Coolant Temp and Engine Speed.
| Tester Display |
|---|
| Engine Speed |
| MAF |
| Coolant Temp |
Allow the engine to idle until Coolant Temp reaches 75°C (167°F) or higher.
Read MAF with the engine speed at 3000 rpm.
| Standard | ||||||
|---|---|---|---|---|---|---|
|
| Result | |||
|---|---|---|---|
|
| NG |
|
GO TO STEP 27 Click here |
| OK |
|
INSPECT SPARK PLUG
Inspect the spark plug of the misfiring cylinder.
| Result | |||
|---|---|---|---|
|
| NG |
|
REPLACE SPARK PLUG Click here |
| OK |
|
CHECK FOR SPARKS (SPARK TEST)
Perform a spark test.
Tech Tips
If the result of the spark test is normal, proceed to the next step.
Perform "Inspection After Repair" after repairing or replacing the ignition system.
| Result | ||
|---|---|---|
|
| NEXT |
|
CHECK CYLINDER COMPRESSION PRESSURE
Measure the cylinder compression pressure of the misfiring cylinder.
Tech Tips
Perform "Inspection After Repair" after repairing or replacing the engine assembly.
| Result | |||
|---|---|---|---|
|
| NG |
|
CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION |
| OK |
|
CHECK TERMINAL VOLTAGE (#10, #20, #30 AND/OR #40)
| *a | Front view of wire harness connector (to ECM) |
Disconnect the ECM connector.
Turn the engine switch on (IG).
Measure the voltage according to the value(s) in the table below.
| Standard Voltage | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
| Result | |||
|---|---|---|---|
|
| NG |
|
CHECK FUEL INJECTOR CIRCUIT Click here |
| OK |
|
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).
| Result | |||
|---|---|---|---|
|
| NG |
|
REPLACE FUEL INJECTOR ASSEMBLY Click here |
| OK |
|
CHECK ENGINE MECHANICAL SYSTEM
Check for mechanical malfunctions that affect the valve timing, such as a jumped tooth or stretching of the timing chain.
| Result | |||
|---|---|---|---|
|
| NG |
|
REPAIR OR REPLACE MALFUNCTIONING PARTS, COMPONENT AND AREA |
| OK |
|
CHECK WHETHER DTC OUTPUT RECURS (DTC P0300, P0301, P0302, P0303 OR P0304)
Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Clear the DTCs.
Turn the engine switch off and wait for at least 30 seconds.
Turn the engine switch on (IG).
Turn the GTS on.
Start the engine.
Warm up the engine.
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.
| Tester Display |
|---|
| All Readiness |
Input the DTC: P0300, P0301, P0302, P0303 or P0304.
Check the DTC judgment result.
| Result | ||||||
|---|---|---|---|---|---|---|
|
| B |
|
CHECK FOR INTERMITTENT PROBLEMS Click here |
| A |
|
CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY CONNECTOR CONNECTION)
Check the connection and terminal contact pressure of connectors and wire harnesses between the mass air flow meter sub-assembly and ECM.
Tech Tips
Repair any problems.
| Result | ||
|---|---|---|
|
| NEXT |
|
CHECK WHETHER DTC OUTPUT RECURS (MISFIRE DTCS)
Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Clear the DTCs.
Turn the engine switch off and wait for at least 30 seconds.
Turn the engine switch on (IG).
Turn the GTS on.
Start the engine.
Warm up the engine.
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.
| Tester Display |
|---|
| All Readiness |
Input the DTC: P0300, P0301, P0302, P0303 or P0304.
Check the DTC judgment result.
| Result | ||||||
|---|---|---|---|---|---|---|
|
| B |
|
END |
| A |
|
CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM)
| Result | |||
|---|---|---|---|
|
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 | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
| Result | |||
|---|---|---|---|
|
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
| OK |
|
REPLACE MASS AIR FLOW METER SUB-ASSEMBLY
Replace the mass air flow meter sub-assembly.
Tech Tips
If the results of the inspections performed in steps 13 and 19 indicated no problem, proceed to the next step without replacing the mass air flow meter sub-assembly.
Perform "Inspection After Repair" after replacing the mass air flow meter sub-assembly.
| Result | ||
|---|---|---|
|
| NEXT |
|
CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED
Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Clear the DTCs.
Turn the engine switch off and wait for at least 30 seconds.
Turn the engine switch on (IG).
Turn the GTS on.
Start the engine.
Warm up the engine.
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.
| Tester Display |
|---|
| All Readiness |
Input the DTC: P0300, P0301, P0302, P0303 or P0304.
Check the DTC judgment result.
| Result | ||||||
|---|---|---|---|---|---|---|
|
| A |
|
END |
| B |
|
REPLACE ECM Click here |
CHECK FUEL LINE
Check the fuel lines for leaks or blockage.
| Result | |||
|---|---|---|---|
|
| OK |
|
REPLACE FUEL PUMP Click here |
| NG |
|
REPAIR OR REPLACE FUEL LINE |