SFI SYSTEM, Diagnostic DTC:P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308

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
P0305 Cylinder 5 Misfire Detected
P0306 Cylinder 6 Misfire Detected
P0307 Cylinder 7 Misfire Detected
P0308 Cylinder 8 Misfire Detected

DESCRIPTION

A015DQEE03

When the engine misfires, high concentrations of hydrocarbons (HC) enter the exhaust gas. Extremely high HC concentration levels can cause increases in exhaust emission levels. High concentrations of HC can also cause increases in the Three-Way Catalytic Converter (TWC) temperature, which may cause damage to the 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 TWC reaches the point of thermal degradation, the MIL blinks. To monitor misfires, the ECM uses both the Camshaft Position (CMP) sensor and the Crankshaft Position (CKP) sensor. The CMP sensor is used to identify any misfiring cylinders and the CKP 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 level, the ECM stores DTC(s).

DTC Code 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):


  • A high temperature misfire occurs in the Three-Way Catalytic Converter (TWC).

  • An emission deterioration misfire occurs.


  • Open or short in engine wire harness

  • Connector connection

  • Vacuum hose connections

  • Ignition system

  • Fuel injector

  • Fuel pressure

  • Mass Air Flow (MAF) meter

  • Engine Coolant Temperature (ECT) sensor

  • Compression pressure

  • Valve timing

  • PCV valve and hose

  • PCV hose connections

  • Air induction system

  • ECM

P0301

P0302

P0303

P0304

P0305

P0306

P0307

P0308

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


  • A high temperature misfire occurs in the Three-Way Catalytic Converter (TWC).

  • An emission deterioration misfire occurs.

Tech Tips

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 stores a DTC when either one of the following conditions, which could cause emission deterioration, is detected (2 trip detection logic).


The ECM flashes the MIL (immediate detection logic) and stores a DTC (2 trip detection logic) when either one of the following conditions, which could cause the Three-Way Catalytic Converter (TWC) damage, is detected.


WIRING DIAGRAM

A0158I5E06
A0155G0E03
A0158L1E02

CONFIRMATION DRIVING PATTERN


  1. Connect the intelligent tester to the DLC3.

  2. Turn the engine switch on (IG).

  3. Turn the tester on.

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

  5. Using the tester, switch the ECM from normal mode to check mode Click here.

  6. Read the misfire counts of each cylinder (cylinder No. 1 to No. 8) with the engine in an idling condition. If any misfire count is displayed, skip the following confirmation driving pattern.

  7. Drive the vehicle several times with the conditions, such as engine speed and engine load, shown in Misfire RPM and Misfire Load in the Data List.

    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 Misfire RPM and Misfire Load in the Data List.

    Engine Speed Duration
    Idling 8 minutes or more
    1000 4.5 minutes or more
    2000 2.5 minutes or more
    3000 1.5 minute or more
  8. Check whether misfires have occurred by checking 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.

  9. Record the DTC(s), freeze frame data and misfire counts.

  10. Turn the engine switch off and wait for at least 5 seconds.

INSPECTION PROCEDURE

Tech Tips


  • DTC P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 and P0308 are for Euro-OBD only.

  • If any DTCs other than misfire DTCs are output, troubleshoot those DTCs first.

  • Read freeze frame data using the intelligent tester. 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 the misfire does not recur when the vehicle is brought to the workshop, reproduce the conditions stored in the freeze frame data.

  • If the misfire still cannot be reproduced even though the conditions stored in the freeze frame data have been duplicated, one of the following factors is considered to be a possible cause of the problem:


    1. The fuel level is low.

    2. Improper fuel is 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, No. 4, No. 5, No. 6, No. 7 and No. 8).

  • Be sure to confirm that no misfiring cylinder DTCs are output again by conducting the confirmation driving pattern after the repairs.

  • For 6 and 8 cylinder engines, the ECM intentionally does not store the specific misfiring cylinder DTCs at high engine speed. If misfires only occur during high engine speed driving, only DTC P0300 is stored.

    In the event of DTC P0300 being present, perform the following operations:


    1. Clear the DTC Click here.

    2. Start the engine and conduct the confirmation driving pattern.

    3. Read the misfiring rates of each cylinder or DTC(s) using the intelligent tester.

    4. Repair the cylinder(s) that has a high misfiring rate or is indicated by the DTC.

    5. After finishing repairs, conduct the confirmation driving pattern again, in order to verify that DTC P0300 is not output.

  • When either Short FT #1, Long FT #1, Short FT #2 or Long FT #2 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 below 75°C (167°F), the misfires occurred only while warming up the engine.

  • An extremely imbalanced drive wheel which causes body vibration may cause misfire DTCs to be detected.

PROCEDURE


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


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the tester on.

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

    5. Read DTCs.

      Result
      Result Proceed to
      P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 and/or P0308 are output A
      P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 and/or P0308 and other DTCs are output B

      Tech Tips

      If any DTCs other than P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 and P0308 are output, troubleshoot those DTCs first.


    B
    A
  2. CHECK PCV HOSE CONNECTIONS


    1. Check the PCV hose connections.

      OK
      PCV hose is connected correctly and is not damaged.

    NG
    OK
  3. READ VALUE USING INTELLIGENT TESTER (MISFIRE RPM AND MISFIRE LOAD)


    1. Connect the intelligent tester the DLC3.

    2. Turn the engine switch on (IG) and turn the tester on.

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

    4. 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.


    NEXT
  4. READ VALUE USING INTELLIGENT TESTER (MISFIRE COUNT)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the tester on.

    4. Clear DTCs Click here.

    5. Enter the following menus: Powertrain / Engine and ECT / Data List / Misfire / Cylinder #1 Misfire Count, #2, #3, #4, #5, #6, #7 and #8.

    6. Allow the engine to idle.

    7. Read each value for Cylinder #1 Misfire Count to #8 displayed on the tester. If no misfire counts occur in any cylinders, perform the following procedures:


      1. Move the shift lever to D.

      2. Check the Cylinder #1 Misfire Count to #8.

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

    8. Drive the vehicle with the Misfire RPM and Misfire Load noted in the "Read Value Using tester (Misfire RPM and Misfire Load)" procedures above (Procedure "A").

    9. Read the Cylinder #1 Misfire Count to #8 or DTCs displayed on the tester (Procedure "B").

      Result
      Misfire Count 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 record of the ECT 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
    A
  5. INSPECT SPARK PLUG


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


    NG
    OK
  6. CHECK FOR SPARKS AND IGNITION


    1. Disconnect the injector connectors to prevent the engine from starting.

      CAUTION:

      Always disconnect all injector connectors.

      Note

      Do not crank the engine for more than 2 seconds.

    2. Remove the ignition coil from the cylinder head Click here.

    3. A015AJB

      Install the spark plug onto the ignition coil.

    4. Attach the spark plug assembly to the cylinder head.

    5. Crank the engine for less than 2 seconds and check the spark.

      OK
      Sparks jump across electrode gap.
    6. Install the ignition coil.

    7. Reconnect the injector connectors.


    NG
    OK
  7. CHECK CYLINDER COMPRESSION PRESSURE


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


    NG
    OK
  8. CHECK FUEL INJECTOR OF MISFIRING CYLINDER


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


    NG
    OK
  9. CHECK HARNESS AND CONNECTOR


    1. Disconnect the fuel injector connector.

    2. Disconnect the C45 ECM connector.

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

      Standard Resistance
      Cylinder Tester Connection Condition Specified Condition
      No. 1 a5-1 - Body ground Always 10 kΩ or higher
      a5-1 - C45-86 (#10) Always Below 1 Ω
      No. 2 a1-1 - Body ground Always 10 kΩ or higher
      a1-1 - C45-109 (#20) Always Below 1 Ω
      No. 3 a6-1 - Body ground Always 10 kΩ or higher
      a6-1 - C45-85 (#30) Always Below 1 Ω
      No. 4 a2-1 - Body ground Always 10 kΩ or higher
      a2-1 - C45-108 (#40) Always Below 1 Ω
      No. 5 a7-1 - Body ground Always 10 kΩ or higher
      a7-1 - C45-84 (#50) Always Below 1 Ω
      No. 6 a3-1 - Body ground Always 10 kΩ or higher
      a3-1 - C45-107 (#60) Always Below 1 Ω
      No. 7 a8-1 - Body ground Always 10 kΩ or higher
      a8-1 - C45-83 (#70) Always Below 1 Ω
      No. 8 a4-1 - Body ground Always 10 kΩ or higher
      a4-1 - C45-106 (#80) Always Below 1 Ω

    NG
    OK
  10. CHECK FUEL INJECTOR OF MISFIRING CYLINDER


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


    NG
    OK
  11. CHECK AIR INDUCTION SYSTEM


    1. Check the air induction system for vacuum leakage Click here.

      OK
      No leakage from air induction system.

    NG
    OK
  12. CHECK FUEL PRESSURE


    1. Check the fuel pressure Click here.


    NG
    OK
  13. READ VALUE USING INTELLIGENT TESTER (COOLANT TEMP)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the tester on.

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

    5. Read the 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).

    NG
    OK
  14. INSPECT MASS AIR FLOW METER


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the tester on.

    4. Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / 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 25.2 gm/s and 35.2 gm/s (shift lever: N; A/C: Off).

    NG
    OK
  15. CHECK VALVE TIMING

    A015ANWE02

    1. Remove the cylinder head cover LH and RH.

    2. Turn the crankshaft pulley, and align its groove with the timing mark "0" of the timing chain cover.

    3. Check that the timing marks of the camshaft timing gears and camshaft timing exhaust gears are at the positions shown in the illustration.

      OK
      Timing marks on camshaft timing gears are aligned as shown in the illustration.

    OK
    NG
  16. CHECK AIR INDUCTION SYSTEM


    1. Check the air induction system for vacuum leakage Click here.

      OK
      No leakage from air induction system.

    NG
    OK
  17. CHECK FUEL PRESSURE


    1. Check the fuel pressure Click here.


    NG
    OK
  18. READ VALUE USING INTELLIGENT TESTER (COOLANT TEMP)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG) and turn the tester on.

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

    4. Read the 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).

    NG
    OK
  19. INSPECT MASS AIR FLOW METER


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the tester on.

    4. Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / 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 25.2 gm/s and 35.2 gm/s (shift lever: N; A/C: Off).

    NG
    OK
  20. CHECK VALVE TIMING

    A015ANWE02

    1. Remove the cylinder head cover LH and RH.

    2. Turn the crankshaft pulley, and align its groove with the timing mark "0" of the timing chain cover.

    3. Check that the timing marks of the camshaft timing gears and camshaft timing exhaust gears are at the positions shown in the illustration.

      OK
      Timing marks on camshaft timing gears are aligned as shown in the illustration.

    NG
    OK
  21. INSPECT SPARK PLUG


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


    NG
    OK
  22. CHECK FOR SPARKS AND IGNITION


    1. Disconnect the injector connectors to prevent the engine from starting.

      CAUTION:

      Always disconnect all injector connectors.

      Note

      Do not crank the engine for more than 2 seconds.

    2. Remove the ignition coil from the cylinder head Click here.

    3. A015AJB

      Install the spark plug onto the ignition coil.

    4. Attach the spark plug assembly to the cylinder head.

    5. Crank the engine for less than 2 seconds and check the spark.

      OK
      Sparks jump across electrode gap.
    6. Install the ignition coil.

    7. Reconnect the injector connectors.


    NG
    OK
  23. CHECK CYLINDER COMPRESSION PRESSURE


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


    NG
    OK
  24. CHECK FUEL INJECTOR ASSEMBLY (POWER SOURCE)

    A015AZFE05

    1. Disconnect the fuel injector connector.

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

      Standard Voltage
      Cylinder Tester Connection Switch Condition Specified Condition
      No. 1 a5-2 - Ground Engine switch on (IG) 11 to 14 V
      No. 2 a1-2 - Ground Engine switch on (IG) 11 to 14 V
      No. 3 a6-2 - Ground Engine switch on (IG) 11 to 14 V
      No. 4 a2-2 - Ground Engine switch on (IG) 11 to 14 V
      No. 5 a7-2 - Ground Engine switch on (IG) 11 to 14 V
      No. 6 a3-2 - Ground Engine switch on (IG) 11 to 14 V
      No. 7 a8-2 - Ground Engine switch on (IG) 11 to 14 V
      No. 8 a4-2 - Ground Engine switch on (IG) 11 to 14 V

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


    1. Disconnect the fuel injector connector.

    2. Disconnect the C45 ECM connector.

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

      Standard Resistance
      Cylinder Tester Connection Condition Specified Condition
      No. 1 a5-1 - Body ground Always 10 kΩ or higher
      a5-1 - C45-86 (#10) Always Below 1 Ω
      No. 2 a1-1 - Body ground Always 10 kΩ or higher
      a1-1 - C45-109 (#20) Always Below 1 Ω
      No. 3 a6-1 - Body ground Always 10 kΩ or higher
      a6-1 - C45-85 (#30) Always Below 1 Ω
      No. 4 a2-1 - Body ground Always 10 kΩ or higher
      a2-1 - C45-108 (#40) Always Below 1 Ω
      No. 5 a7-1 - Body ground Always 10 kΩ or higher
      a7-1 - C45-84 (#50) Always Below 1 Ω
      No. 6 a3-1 - Body ground Always 10 kΩ or higher
      a3-1 - C45-107 (#60) Always Below 1 Ω
      No. 7 a8-1 - Body ground Always 10 kΩ or higher
      a8-1 - C45-83 (#70) Always Below 1 Ω
      No. 8 a4-1 - Body ground Always 10 kΩ or higher
      a4-1 - C45-106 (#80) Always Below 1 Ω

    NG
    OK
  26. CHECK FUEL INJECTOR ASSEMBLY OF MISFIRING CYLINDER

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


    NG
    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 and ECM Click here.

      Tech Tips

      Repair any problems.


    NEXT
  28. CHECK WHETHER DTC OUTPUT RECURS


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the tester on.

    4. Clear the DTCs Click here.

    5. Turn the engine switch off.

    6. Turn the engine switch on (IG) and turn the tester on.

    7. Start the engine and warm it up.

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

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

    10. Input the DTC: P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 or P0308.

    11. Check the DTC judgment result.

      Result
      Display (DTC Output) Proceed to

      ABNORMAL

      (P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 or P0308 output)

      A

      NORMAL

      (No DTC output)

      B

    B
    A
  29. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)


    1. Disconnect the mass air flow meter 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
      C50-3 (VG) - C45-74 (VG) Always Below 1 Ω
      C50-2 (E2G) - C45-75 (E2G) Always Below 1 Ω
      C50-3 (VG) or C45-74 (VG) - Body ground Always 10 kΩ or higher

    NG
    OK
  30. REPLACE MASS AIR FLOW METER

    Replace the mass air flow meter assembly Click here.

    Tech Tips

    If the results of the inspections performed in steps 14 and 21 indicated no problem, proceed to the next step without replacing the mass air flow meter assembly.


    NEXT
  31. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the tester on.

    4. Clear the DTCs Click here.

    5. Turn the engine switch off.

    6. Turn the engine switch on (IG) and turn the tester on.

    7. Start the engine and warm it up.

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

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

    10. Input the DTC: P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 or P0308.

    11. Check the DTC judgment result.

      Result
      Display (DTC Output) Proceed to

      NORMAL

      (No DTC output)

      A

      ABNORMAL

      (P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 or P0308 output)

      B

    B
    A
  32. CHANGE TO CHANGE TO NORMAL SPARK PLUG AND CHECK SPARK OF MISFIRING CYLINDER


    1. Change the installed spark plug to a spark plug that functions normally.

    2. Perform a spark test.

      CAUTION:

      Always disconnect all injector connectors.

      Note

      Do not crank the engine for more than 2 seconds.


      1. Install the spark plug to the ignition coil and connect the ignition coil connector.

      2. Disconnect the injector connector.

      3. Ground the spark plug.

      4. Check if sparks occur while the engine is being cranked.

        OK
        Sparks jump across electrode gap.

    NG
    OK
  33. CHANGE TO NORMAL IGNITION COIL AND CHECK SPARK OF MISFIRING CYLINDER


    1. Change the ignition coil to an ignition coil that functions normally.

    2. Perform a spark test.

      CAUTION:

      Always disconnect all injector connectors.

      Note

      Do not crank the engine for more than 2 seconds.


      1. Install the spark plug to the ignition coil and connect the ignition coil connector.

      2. Disconnect the injector connector.

      3. Ground the spark plug.

      4. Check if sparks occur while the engine is being cranked.

        OK
        Sparks jump across electrode gap.

    NG
    OK
  34. CHECK FUEL LINE


    1. Check the fuel lines for leaks or blockage.


    NG
    OK