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

When the engine misfires, high concentrations of hydrocarbons (HC) enter the exhaust gas. Extremely high HC concentration levels can cause an increase 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 this increase 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 ECM blinks the MIL. 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 when the crankshaft rotation speed variations exceed predetermined thresholds.

If the misfire exceeds the threshold levels and may cause emission 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):


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

  • Emission deterioration misfire occurs (MIL illuminates)

  • Open or short in engine wire harness

  • Connector connection

  • Vacuum hose connections

  • Ignition system

  • Fuel injector (for direct injection)

  • Fuel injector (for port injection)

  • 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 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)

  • Emission deterioration misfire occurs (MIL illuminates)

  • Open or short in engine wire harness

  • Connector connection

  • Vacuum hose connections

  • Ignition system

  • Fuel injector (for direct injection)

  • Fuel injector (for port injection)

  • 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

If DTCs that indicate misfires are set for different cylinders, but DTC P0300 is not set, it indicates that misfires have been detected in different cylinders at different times. DTC P0300 is only set when several misfiring cylinders are detected at the same time.

MONITOR DESCRIPTION

The ECM illuminates the MIL and sets 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 sets 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:


CONFIRMATION DRIVING PATTERN


  1. Connect the intelligent tester to the DLC3.

  2. Turn the power 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. Turn the power switch on (READY).

  7. Read the misfire counts of each cylinder (Cylinder #1 Misfire Count to Cylinder #8 Misfire Count) with the engine in an idling condition. If any misfire count is displayed, skip the following confirmation driving pattern.

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

    Tech Tips

    In order to store misfire DTCs using the Misfire RPM and Misfire Load in the Data List, it is necessary to operate the vehicle for the period of time shown in the table below.

    Engine RPM Duration
    Idling 5 minutes or more
    1000 4 minutes or more
    2000 2 minutes or more
    3000 1.5 minute or more

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

    Tech Tips

    Do not turn the power 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 erased.

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

  11. Turn the power switch off and wait for at least 5 seconds.

INSPECTION PROCEDURE

Tech Tips


  • 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.

  • When viewed from the rear of the engine assembly, Bank 1 is on the left side and Bank 2 is on the right side.

  • 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 is considered to be a possible cause of the problem:


    1. There was insufficient fuel in the tank.

    2. Improper fuel is used.

    3. The spark plugs have been contaminated.

    4. The problem requires further diagnosis.

  • After finishing repairs, check the misfire counts of the cylinders (Cylinder #1 Misfire Count to Cylinder #8 Misfire Count).

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

  • For 6 and 8 cylinder engines, the ECM intentionally does not set the specific misfiring cylinder DTCs at high engine RPM. If misfires occur only in high engine RPM areas, only DTC P0300 is set.

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


    1. Turn the power switch on (READY).

    2. Clear the DTC Click here.

    3. Conduct the confirmation driving pattern.

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

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

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

  • When one of 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 less than 75°C (167°F), the misfires have occurred only while warming up the engine.

PROCEDURE


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


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the tester ON.

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

    5. Read DTCs.

      Result
      Display (DTC output) Proceed to
      P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 and/or P0308 A
      P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 and/or P0308 and other DTCs 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

    GO TO DTC CHART Click here

    A

  2. READ VALUE USING INTELLIGENT TESTER (MISFIRE RPM AND MISFIRE LOAD)


    1. Connect the intelligent tester to the DLC3.

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

    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

  3. CHECK MISFIRE COUNT OF PORT INJECTION


    1. Put the engine in inspection mode Click here.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the tester ON.

    4. Clear DTCs Click here.

    5. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Way / Port. (Procedure "A")

    6. Allow the engine to idle.

    7. Monitor all of the misfire rate values that are displayed on the tester: Powertrain / Engine and ECT / Data List / Misfire / Cylinder #1 Misfire Count to Cylinder #8 Misfire Count.

      If no misfire counts occur for any of the cylinders, perform the following procedure: (Procedure "B")


      1. Move the shift lever to the D position.

      2. Repeat procedure "A" to "B" above.

      3. Monitor all of the misfire count values that are displayed on the tester.

        Result
        Misfire count Proceed to
        1 or 2 cylinders have misfire counts A
        3 cylinders or more have misfire counts A
        There are no misfire counts B

    B

    CHECK MISFIRE COUNT OF DIRECT INJECTION Click here

    A

  4. CHECK MISFIRE COUNT OF DIRECT INJECTION


    1. Put the engine in inspection mode Click here.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the tester ON.

    4. Clear DTCs Click here.

    5. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Way / Direct. (Procedure "A")

    6. Allow the engine to idle.

    7. Monitor all of the misfire rate values that are displayed on the tester: Powertrain / Engine and ECT / Data List / Misfire / Cylinder #1 Misfire Count to Cylinder #8 Misfire Count.

      If no misfire counts occur for any of the cylinders, perform the following procedure: (Procedure "B")


      1. Move the shift lever to the D position.

      2. Repeat procedure "A" to "B" above.

      3. Monitor all of the misfire count values that are displayed on the tester.

        Result
        Misfire Count Proceed to
        Port Direct
        1 or 2 cylinders have misfire counts 1 or 2 cylinders have misfire counts A
        3 cylinders or more have misfire counts 3 cylinders or more have misfire counts B
        1 or 2 cylinders have misfire counts There are no misfire counts C
        3 cylinders or more have misfire counts There are no misfire counts D

    B

    CHECK PCV HOSE (HOSE CONNECTIONS) Click here

    C

    REPLACE FUEL INJECTOR (for Port Injection) (MISFIRING CYLINDER) Click here

    D

    CHECK FUEL PRESSURE (LOW PRESSURE SIDE) Click here

    A

  5. CHECK SPARK PLUG


    1. Check the spark plug Click here.


    NG

    REPLACE SPARK PLUG Click here

    OK

  6. CHECK FOR SPARK AND IGNITION


    1. Check for spark and ignition Click here.


    NG

    CHANGE TO NORMAL SPARK PLUG AND CHECK SPARK OF MISFIRING CYLINDER Click here

    OK

  7. CHECK CYLINDER COMPRESSION PRESSURE (MALFUNCTIONING CYLINDER)


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


    NG

    CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

    OK

    REPLACE ECM Click here

  8. 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 Click here.

      OK
      Sparks jump across the electrode gap.

    NG

    REPLACE IGNITION COIL ASSEMBLY THEN CONFIRM THAT THERE IS NO MISFIRE Click here

    OK

    REPLACE SPARK PLUG Click here

  9. CHECK PCV HOSE (HOSE CONNECTIONS)

    OK
    PCV hose is connected correctly and is not damaged.

    NG

    REPLACE PCV HOSE

    OK

  10. CHECK AIR INDUCTION SYSTEM


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

      OK
      No leakage from air induction system.

    NG

    REPAIR OR REPLACE AIR INDUCTION SYSTEM

    OK

  11. READ VALUE USING INTELLIGENT TESTER (COOLANT TEMP)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power 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 Data List twice, when the engine is both cold and warmed up.

      Standard
      With cold engine
      Same as ambient air temperature
      With warm engine
      75 to 95°C (167 to 203°F)

    NG

    REPLACE ENGINE COOLANT TEMPERATURE SENSOR Click here

    OK

  12. INSPECT MASS AIR FLOW METER (for Bank 1 and Bank 2)


    1. Inspect the mass air flow meter Click here.


    NG

    REPLACE MASS AIR FLOW METER Click here

    OK

  13. CHECK VALVE TIMING

    A01H25AE01

    1. Remove the cylinder head cover sub-assembly (for Bank 1 and Bank 2) Click here.

    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.

    4. Reinstall the cylinder head cover sub-assembly (for Bank 1 and Bank 2) Click here.


    NG

    ADJUST VALVE TIMING Click here

    OK

    REPLACE ECM Click here

  14. CHECK FUEL PRESSURE (LOW PRESSURE SIDE)


    1. Check the fuel pressure (low pressure side) Click here.


    NG

    CHECK FUEL PUMP OPERATION Click here

    OK

    REPLACE FUEL INJECTOR (for Port Injection) Click here

  15. CHECK FUEL PUMP OPERATION


    1. Check the fuel pump operation Click here.


    NG

    REPLACE FUEL PUMP Click here

    OK

    CHECK AND REPLACE FUEL SYSTEM (PRESSURE REGULATOR, PIPE LINE AND FILTER)

  16. CHECK MISFIRE COUNT OF DIRECT INJECTION


    1. Put the engine in inspection mode Click here.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the tester ON.

    4. Clear DTCs Click here.

    5. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Way / Direct. (Procedure "A")

    6. Allow the engine to idle.

    7. Monitor all of the misfire count values that are displayed on the tester: Powertrain / Engine and ECT / Data List / Misfire / Cylinder #1 Misfire Count to Cylinder #8 Misfire Count.

      If no misfire counts occur for any of the cylinders, perform the following procedure: (Procedure "B")


      1. Move the shift lever to the D position.

      2. Repeat procedure "A" to "B" above.

      3. Monitor all of the misfire count values that are displayed on the tester.

        Result
        Misfire Count Proceed to
        Port Direct
        There are no misfire counts There are misfire counts A
        There are no misfire counts There are no misfire counts B

    B

    CHECK MISFIRE COUNT Click here

    A

    REPLACE FUEL INJECTOR (for Direct Injection) (MISFIRING CYLINDER) Click here

  17. CHECK MISFIRE COUNT


    1. Put the engine in inspection mode Click here.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the tester ON.

    4. Clear DTCs Click here.

    5. Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Misfire RPM, Misfire Load, Cylinder #1 Misfire Count to Cylinder #8 Misfire Count and Injection Way.

    6. Drive the vehicle with Misfire RPM and Misfire Load.

    7. Monitor all of the misfire count values or DTCs and Injection Way displayed on the tester.

      Result
      Misfire count Injection Way Proceed to
      There are no misfire counts - A
      1 or 2 cylinders have misfire counts Either B
      3 cylinders or more have misfire counts Either C
      There are misfire counts Direct D

    B

    CHECK SPARK PLUG Click here

    C

    CHECK PCV HOSE (HOSE CONNECTIONS) Click here

    D

    REPLACE FUEL INJECTOR (for Direct Injection) Click here

    A

    CHECK FOR INTERMITTENT PROBLEMS Click here

  18. CHECK SPARK PLUG


    1. Check the spark plug Click here.


    NG

    REPLACE SPARK PLUG Click here

    OK

  19. CHECK FOR SPARK AND IGNITION


    1. Check for spark and ignition Click here.


    NG

    CHANGE TO NORMAL SPARK PLUG AND CHECK SPARK OF MISFIRING CYLINDER Click here

    OK

  20. CHECK CYLINDER COMPRESSION PRESSURE (MALFUNCTIONING CYLINDER)


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


    NG

    CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

    OK

    REPLACE ECM Click here

  21. CHECK PCV HOSE (HOSE CONNECTIONS)

    OK
    PCV hose is connected correctly and is not damaged.

    NG

    REPLACE PCV HOSE

    OK

  22. CHECK AIR INDUCTION SYSTEM


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


    NG

    REPAIR OR REPLACE AIR INDUCTION SYSTEM

    OK

  23. READ VALUE USING INTELLIGENT TESTER (COOLANT TEMP)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power 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 Data List twice, when the engine is both cold and warmed up.

      Standard
      With cold engine
      Same as ambient air temperature
      With warm engine
      75 to 95°C (167 to 203°F)

    NG

    REPLACE ENGINE COOLANT TEMPERATURE SENSOR Click here

    OK

  24. INSPECT MASS AIR FLOW METER (for Bank 1 and Bank 2)


    1. Inspect the mass air flow meter Click here.


    NG

    REPLACE MASS AIR FLOW METER Click here

    OK

  25. INSPECT VALVE TIMING

    A01H25AE01

    1. Remove the cylinder head cover sub-assembly (for Bank 1 and Bank 2) Click here.

    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.

    4. Reinstall the cylinder head cover sub-assembly (for Bank 1 and Bank 2) Click here.


    NG

    ADJUST VALVE TIMING Click here

    OK

    REPLACE ECM Click here

  26. 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 Click here.

      OK
      Sparks jump across the electrode gap.

    NG

    REPLACE IGNITION COIL ASSEMBLY THEN CONFIRM THAT THERE IS NO MISFIRE Click here

    OK

    REPLACE SPARK PLUG Click here