SFI SYSTEM, Diagnostic DTC:P0300, P0301, P0302, P0303, P0304

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

B001EMGE24
Text in Illustration
*1 Camshaft Position Sensor
*2 Crankshaft Position Sensor
*3 ECM

When the engine misfires, high concentrations of hydrocarbons (HC) enter the exhaust gas. Extremely high HC concentration levels can cause increases in exhaust emissions levels. High concentrations of HC can also cause increases in the Three-way Catalytic Converter (TWC) temperature, which may cause damage to the Three-way Catalytic Converter (TWC). To prevent these increases 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 (TWC) reaches the point of thermal degradation, the MIL blinks. 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 as when the crankshaft rotation speed variations exceed predetermined thresholds.

If the misfire rate exceeds the threshold, the ECM illuminates the MIL and stores 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):


  • Misfire occurs that may damage the three-way catalytic converter (MIL blinks when detect immediately).

  • Catalyst deterioration misfire occurs (MIL illuminates).

  • Open or short in engine wire harness

  • Connector connection

  • Vacuum hose connections

  • Ignition system

  • Fuel injector assembly

  • Fuel pressure

  • Mass air flow meter sub-assembly

  • Engine coolant temperature sensor

  • Compression pressure

  • Valve timing

  • PCV valve and hose

  • PCV hose connections

  • Intake system

  • ECM

P0301

P0302

P0303

P0304

Misfiring of specific cylinder occurs and one of the following conditions below is detected (2 trip detection logic):


  • Misfire occurs that may damage the three-way catalytic converter (MIL blinks when detect immediately).

  • Catalyst deterioration misfire occurs (MIL illuminates).

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 stores a DTC when the following condition, which could cause catalyst deterioration, is detected (2 trip detection logic).


The ECM flashes the MIL immediately when the following condition, which could cause three-way catalytic converter damage, is detected. Also, the ECM stores a DTC when the following condition is detected (2 trip detection logic).


MONITOR STRATEGY

Required Sensors/Components (Main) Crankshaft position sensor and camshaft position sensor
Required Sensors/Components (Related) Engine coolant temperature, intake air temperature sensors and mass air flow meter sub-assembly
Frequency of Operation Continuous

TYPICAL ENABLING CONDITIONS

Misfire
Intake air temperature Higher than -10°C (14°F)
Either of following conditions (a) or (b) met -
(a) Engine coolant temperature at engine start Higher than -7°C (19°F)
(b) Engine coolant temperature Higher than 20°C (68°F)
Monitor Period of Emissions-related Misfire
Duration 1000 crankshaft revolutions x 4
Monitor Period of Catalyst-damaging Misfire (MIL Blinks)
Duration 200 crankshaft revolutions x 3

WIRING DIAGRAM

Refer to DTC P0351 Click here for the wiring diagram of the ignition system.

Refer to Fuel Injector Circuit Click here.

CONFIRMATION DRIVING PATTERN


  1. Connect the GTS to the DLC3.

  2. Turn the ignition switch to ON.

  3. Turn the GTS on.

  4. Record the DTC(s) and freeze frame data.

  5. Clear the DTCs (even if no DTCs are stored, perform the clear DTC operation).

  6. Using the GTS, switch the ECM from normal mode to check mode Click here.

  7. Read the misfire counts of each cylinder (cylinder No. 1 to No. 4) with the engine idling. If any misfire count is displayed, skip the following confirmation driving pattern.

  8. 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.

    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 with the engine speed and engine load the same as Misfire RPM and Misfire Load in the freeze frame data.

    Engine Speed 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

  9. Check whether misfires have occurred by checking DTCs and freeze frame data.

    Tech Tips

    Do not turn the ignition 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.

  10. Record the DTCs, freeze frame data and misfire counts.

  11. Turn the ignition switch off and wait for at least 30 seconds.

  12. Clear the DTCs (even if no DTCs are stored, perform the clear DTC operation).

CAUTION / NOTICE / HINT

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 DTC, "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. Freeze frame data records the engine condition when malfunctions are detected. 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 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 misfiring 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:


    1. The fuel level is low.

    2. Improper fuel is being used.

    3. 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 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 more).

  • When Coolant Temp in the freeze frame data is below 75°C (167°F), the misfires may 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


  1. CHECK FOR ANY OTHER DTCS OUTPUT (IN ADDITION TO MISFIRE CODES)


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

    5. Read the DTCs.

      Result
      Result Proceed to
      P0300, P0301, P0302, P0303 and/or P0304 is output A
      P0300, P0301, P0302, P0303 and/or P0304 and other DTCs are output B

      Tech Tips

      If any DTCs other than P0300, P0301, P0302, P0303 and P0304 are output, troubleshoot those DTCs first.


    B

    GO TO DTC CHART Click here

    A

  2. CHECK PCV HOSE CONNECTIONS


    1. Check the PCV hose connections Click here.

      OK
      PCV hose is connected correctly and is not damaged.

    NG

    REPAIR OR REPLACE PCV HOSE Click here

    OK

  3. READ VALUE USING GTS (MISFIRE RPM AND MISFIRE LOAD)


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine and ECT / Data List / Misfire RPM and Misfire Load.

    5. 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 misfire occurred.


    NEXT

  4. READ VALUE USING GTS (MISFIRE COUNT)


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Clear the DTCs Click here.

    5. Enter the following menus: Powertrain / Engine and ECT / Data List / Cylinder #1 Misfire Count, #2, #3 and #4.

    6. Allow the engine to idle.

    7. Read the values for Cylinder #1 Misfire Count to Cylinder #4 Misfire Count displayed on the GTS. If no misfire counts occur in any cylinders, perform the following procedures:


      1. Check Cylinder #1 Misfire Count to Cylinder #4 Misfire Count.

      2. If misfire counts are still not displayed, perform procedures "A" and "B", and then check the misfire counts again.

        Procedure A: Drive the vehicle while matching the vehicle conditions to the Misfire RPM and Misfire Load values noted in the "Read Value Using GTS (Misfire RPM and Misfire Load)" procedure above.

        Procedure B: Read Cylinder #1 Misfire Count to Cylinder #4 Misfire Count or the DTCs output on the GTS.

        Result
        Result Proceed to
        Most misfires occur in only 1 or 2 cylinders A
        3 cylinders or more have equal misfire counts B

        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's record of the engine coolant temperature is below 75°C (167°F), misfire may be detected only when the engine is cold.

        • If the freeze frame data's record of the Engine Run Time is less than 120 seconds, misfire may be detected immediately after the engine is started.


    B

    CHECK INTAKE SYSTEM Click here

    A

  5. INSPECT SPARK PLUG


    1. Inspect the spark plug of the misfiring cylinder Click here.

      Tech Tips

      Perform "Inspection After Repair" after replacing the spark plug Click here.


    NG

    REPLACE SPARK PLUG

    OK

  6. CHECK FOR SPARK (SPARK TEST)


    1. Perform a spark test Click here.

      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 Click here.


    NEXT

  7. CHECK CYLINDER COMPRESSION PRESSURE


    1. Measure the cylinder compression pressure of the misfiring cylinder Click here.

      Tech Tips

      Perform "Inspection After Repair" after repairing or replacing the engine assembly Click here.


    NG

    CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

    OK

  8. CHECK FUEL INJECTOR ASSEMBLY (POWER SOURCE)

    B001H46E04
    Text in Illustration
    *a

    Front view of wire harness connector

    (to Fuel Injector Assembly)

    1. Disconnect the fuel injector connector.

    2. Turn the ignition switch to ON.

    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      C50-1 - Body ground Ignition switch ON 11 to 14 V
      C2-1 - Body ground Ignition switch ON 11 to 14 V
      C51-1 - Body ground Ignition switch ON 11 to 14 V
      C4-1 - Body ground Ignition switch ON 11 to 14 V

    NG

    GO TO FUEL INJECTOR CIRCUIT Click here

    OK

  9. CHECK HARNESS AND CONNECTOR (FUEL INJECTOR - ECM)


    1. Disconnect the fuel injector connector.

    2. Disconnect the ECM connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      C50-2 - C154-4 (#10) Always Below 1 Ω
      C2-2 - C154-3 (#20) Always Below 1 Ω
      C51-2 - C154-2 (#30) Always Below 1 Ω
      C4-2 - C154-1 (#40) Always Below 1 Ω
      C50-2 or C154-4 (#10) - Body ground Always 10 kΩ or higher
      C2-2 or C154-3 (#20) - Body ground Always 10 kΩ or higher
      C51-2 or C154-2 (#30) - Body ground Always 10 kΩ or higher
      C4-2 or C154-1 (#40) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  10. CHECK FUEL INJECTOR ASSEMBLY OF MISFIRING CYLINDER


    1. Check the fuel injector injection [whether fuel volume is high or low, and whether injection pattern is poor] Click here.

      Tech Tips

      Perform "Inspection After Repair" after replacing the fuel injector assembly Click here.


    NG

    REPLACE FUEL INJECTOR ASSEMBLY Click here

    OK

  11. CHECK INTAKE SYSTEM


    1. Check the intake system for vacuum leaks.

      OK
      No leakage in intake system.

      Tech Tips

      Perform "Inspection After Repair" after repairing or replacing the intake system Click here.


    NG

    REPAIR OR REPLACE INTAKE SYSTEM

    OK

  12. CHECK FUEL PRESSURE


    1. Check the fuel pressure Click here.


    NG

    CHECK FUEL LINE Click here

    OK

  13. READ VALUE USING GTS (COOLANT TEMP)


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.

    5. Read Coolant Temp twice, when the engine is both cold and warmed up.

      Standard
      With cold engine: Same as ambient air temperature.
      With warm engine: Between 75°C and 100°C (167°F and 212°F).

      Tech Tips

      Perform "Inspection After Repair" after replacing the engine coolant temperature sensor Click here.


    NG

    REPLACE ENGINE COOLANT TEMPERATURE SENSOR Click here

    OK

  14. READ VALUE USING GTS (MAF)


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine and ECT / Data List / MAF and Coolant Temp.

    5. Allow the engine to idle until Coolant Temp reaches 75°C (167°F) or higher.

    6. Read MAF with the engine speed at 3000 rpm.

      Standard
      Between 6.0 gm/sec and 18.0 gm/sec (shift lever: N; A/C: Off).

    NG

    CHECK HARNESS AND CONNECTOR Click here

    OK

  15. CHECK ENGINE MECHANICAL SYSTEM (CHECK FOR LOOSE TIMING CHAIN AND JUMPED TEETH)

    Check for mechanical malfunctions that affect the valve timing, such as a jumped tooth or stretching of the timing chain.


    OK

    CHECK HARNESS AND CONNECTOR Click here

    NG

    CHECK MALFUNCTIONING PARTS, COMPONENT AND AREA

  16. CHECK INTAKE SYSTEM


    1. Check the intake system for vacuum leaks.

      OK
      No leakage in intake system.

      Tech Tips

      Perform "Inspection After Repair" after repairing or replacing the intake system Click here.


    NG

    REPAIR OR REPLACE INTAKE SYSTEM

    OK

  17. CHECK FUEL PRESSURE


    1. Check the fuel pressure Click here.


    NG

    CHECK FUEL LINE Click here

    OK

  18. READ VALUE USING GTS (COOLANT TEMP)


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.

    5. Read Coolant Temp twice, when the engine is both cold and warmed up.

      Standard
      With cold engine: Same as ambient air temperature.
      With warm engine: Between 75°C and 100°C (167°F and 212°F).

      Tech Tips

      Perform "Inspection After Repair" after replacing the engine coolant temperature sensor Click here.


    NG

    REPLACE ENGINE COOLANT TEMPERATURE SENSOR Click here

    OK

  19. READ VALUE USING GTS (MAF)


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine and ECT / Data List / MAF and Coolant Temp.

    5. Allow the engine to idle until Coolant Temp reaches 75°C (167°F) or higher.

    6. Read MAF with the engine speed at 3000 rpm.

      Standard
      Between 6.0 gm/sec and 18.0 gm/sec (shift lever: N; A/C: Off).

    NG

    CHECK HARNESS AND CONNECTOR Click here

    OK

  20. CHECK ENGINE MECHANICAL SYSTEM (CHECK FOR LOOSE TIMING CHAIN AND JUMPED TEETH)

    Check for mechanical malfunctions that affect the valve timing, such as a jumped tooth or stretching of the timing chain.


    NG

    CHECK MALFUNCTIONING PARTS, COMPONENT AND AREA

    OK

  21. INSPECT SPARK PLUG


    1. Inspect the spark plug of the misfiring cylinder Click here.

      Tech Tips

      Perform "Inspection After Repair" after replacing the spark plug Click here.


    NG

    REPLACE SPARK PLUG

    OK

  22. CHECK FOR SPARK (SPARK TEST)


    1. Perform a spark test Click here.

      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 Click here.


    NEXT

  23. CHECK CYLINDER COMPRESSION PRESSURE


    1. Measure the cylinder compression pressure of the misfiring cylinder Click here.

      Tech Tips

      Perform "Inspection After Repair" after repairing or replacing the engine assembly Click here.


    NG

    CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

    OK

  24. CHECK FUEL INJECTOR ASSEMBLY (POWER SOURCE)

    B001H46E03
    Text in Illustration
    *a

    Front view of wire harness connector

    (to Fuel Injector Assembly)

    1. Disconnect the fuel injector connector.

    2. Turn the ignition switch to ON.

    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      C50-1 - Body ground Ignition switch ON 11 to 14 V
      C2-1 - Body ground Ignition switch ON 11 to 14 V
      C51-1 - Body ground Ignition switch ON 11 to 14 V
      C4-1 - Body ground Ignition switch ON 11 to 14 V

    NG

    GO TO FUEL INJECTOR CIRCUIT Click here

    OK

  25. CHECK HARNESS AND CONNECTOR (FUEL INJECTOR - ECM)


    1. Disconnect the fuel injector connector.

    2. Disconnect the ECM connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      C50-2 - C154-4 (#10) Always Below 1 Ω
      C2-2 - C154-3 (#20) Always Below 1 Ω
      C51-2 - C154-2 (#30) Always Below 1 Ω
      C4-2 - C154-1 (#40) Always Below 1 Ω
      C50-2 or C154-4 (#10) - Body ground Always 10 kΩ or higher
      C2-2 or C154-3 (#20) - Body ground Always 10 kΩ or higher
      C51-2 or C154-2 (#30) - Body ground Always 10 kΩ or higher
      C4-2 or C154-1 (#40) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  26. CHECK FUEL INJECTOR ASSEMBLY OF MISFIRING CYLINDER


    1. Check the fuel injector injection [whether fuel volume is high or low, and whether injection pattern is poor] Click here.

      Tech Tips

      Perform "Inspection After Repair" after replacing the fuel injector assembly Click here.


    NG

    REPLACE FUEL INJECTOR ASSEMBLY Click here

    OK

  27. CHECK HARNESS AND CONNECTOR


    1. Check the connection and terminal contact pressure of connectors and wire harnesses between the mass air flow meter sub-assembly and ECM Click here.

      Tech Tips

      Repair any problems.


    NEXT

  28. CHECK WHETHER DTC OUTPUT RECURS (DTC P0300, P0301, P0302, P0303 or P0304)


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Clear the DTCs Click here.

    5. Turn the ignition switch off and wait for at least 30 seconds.

    6. Start the engine and warm it up.

    7. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

    8. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

    9. Input the DTC: P0300, P0301, P0302, P0303 or P0304.

    10. Check the DTC judgment result.

      Result
      Result Proceed to

      ABNORMAL

      (P0300, P0301, P0302, P0303 or P0304 is output)

      		 A

      NORMAL

      (No DTC is output)

      		 B

    B

    END

    A

  29. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM)


    1. Disconnect the mass air flow meter sub-assembly connector.

    2. Disconnect the ECM connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      C33-3 (VG) - C154-24 (VG) Always Below 1 Ω
      C33-2 (E2G) - C154-32 (E2G) Always Below 1 Ω
      C33-3 (VG) or C154-24 (VG) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  30. REPLACE MASS AIR FLOW METER SUB-ASSEMBLY


    1. Replace the mass air flow meter sub-assembly Click here.

      Tech Tips


      • If the results of the inspections performed in steps 14 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 Click here.


    NEXT

  31. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Clear the DTCs Click here.

    5. Turn the ignition switch off and wait for at least 30 seconds.

    6. Start the engine and warm it up.

    7. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

    8. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

    9. Input the DTC: P0300, P0301, P0302, P0303 or P0304.

    10. Check the DTC judgment result.

      Result
      Result Proceed to

      NORMAL

      (No DTC is output)

      		 A

      ABNORMAL

      (P0300, P0301, P0302, P0303 or P0304 is output)

      		 B

    A

    END

    B

    REPLACE ECM Click here

  32. CHECK FUEL LINE


    1. Check the fuel lines for leaks or blockage.

      Result
      Result Proceed to
      NG A
      OK (for 5 door) B
      OK (for 3 door) C

      Tech Tips

      Perform "Inspection After Repair" after replacing the fuel pump Click here.


    A

    REPAIR OR REPLACE FUEL LINE

    B

    REPLACE FUEL PUMP Click here

    C

    REPLACE FUEL PUMP Click here