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

A0054LZE01
Text in Illustration
*1 VVT Sensor
*2 CKP Sensor
*3 ECM

When the engine misfires, high concentrations of hydrocarbons enter the exhaust gas. Extremely high hydrocarbon concentration levels can cause increases in exhaust emission levels. 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 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 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 as when the crankshaft rotation speed variations exceed predetermined thresholds.

If the misfire rate exceeds the threshold level and could 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 detected

(2 trip detection logic)

  • Open or short in engine wire harness

  • Connector connection

  • Vacuum hose connections

  • Ignition system

  • Injector

  • Fuel pressure

  • Mass air flow meter

  • Engine coolant temperature sensor

  • Compression pressure

  • Valve timing

  • PCV valve and hose

  • PCV hose connection

  • Intake system

  • ECM

P0301

P0302

P0303

P0304

Misfiring of specific cylinder detected

(2 trip detection logic)

When DTCs for misfiring cylinders are randomly set, 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.

WIRING DIAGRAM

A0052ZNE01

CONFIRMATION DRIVING PATTERN


  1. Connect the intelligent tester to the DLC3.

  2. Turn the ignition switch to ON.

  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 #1 to #4) with the engine idling. 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, using the Misfire RPM and Misfire Load in the Data List.

    Engine Speed Duration
    Idling 8 minutes or more
    1000 4 minutes 30 seconds or more
    2000 2 minutes 30 seconds or more
    3000 1 minute 30 seconds or more

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

    Tech Tips

    Do not turn the ignition 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 ignition switch off and wait for 5 seconds.

CAUTION / NOTICE / HINT

Note

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

Tech Tips


  • Check "Fuel Cut Elps Time" in the Data List or the Freeze Frame Data. If the elapsed time is over 0sec, then the engine speed is high (rpm at which fuel cut occurs +500 rpm). When this has happened, there is a possibility that the valve rocker arm will become loose and a fire could start, so check that the valve rocker arm is properly attached Click here.

  • 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 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 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.

    4. The problem is complex and involves multiple factors.

  • After finishing repairs, check that no misfire occurs in each cylinder (Cylinder #1, #2, #3 and #4).

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

  • When either Short FT #1 or Long FT #1 values in the freeze frame data is not within 20% of the central value, 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 occurred only while warming up the engine.

PROCEDURE


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


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

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

    5. Read the DTCs.

      Result
      Display (DTC Output) Proceed to
      P0300, P0301, P0302, P0303 and/or P0304 A
      P0300, P0301, P0302, P0303 and/or P0304 and other DTCs 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. READ VALUE USING INTELLIGENT TESTER (MISFIRE RPM AND MISFIRE LOAD)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON and turn the tester on.

    3. Enter the following menus: Powertrain / Engine and ECT / Data List / 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 PCV HOSE CONNECTIONS

    OK
    PCV hose is correctly connected and is not damaged.

    NG

    REPAIR OR REPLACE PCV HOSE

    OK

  4. READ VALUE USING INTELLIGENT TESTER (MISFIRE COUNT)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

    4. Enter the following menus: Powertrain / Engine and ECT / Data List / Cylinder #1 (to #4) Misfire Count.

    5. 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.

    6. Read Cylinder #1 (to #4) Misfire Count or the DTCs displayed on the tester.

      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's 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's 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

  5. CHECK SPARK PLUG


    1. A00565NE23
      *1 Electrode Gap

      Remove the ignition coil and the spark plug of the misfiring cylinder.

    2. Measure the spark plug electrode gap.

      Maximum gap
      1.0 to 1.3 mm (0.0394 to 0.0512 in.)

    3. Check the electrode for carbon deposits.

      Recommended spark plug:
      Manufacturer Product
      DENSO SC20HR11

      Note

      If the electrode gap is larger than 1.3 mm, replace the spark plug. Do not adjust the electrode gap.

    4. Reinstall the ignition coil and the spark plug.


    NG

    REPLACE SPARK PLUG Click here

    OK

  6. CHECK FOR SPARK AND IGNITION


    1. A0058NV

      Perform a spark test.

      CAUTION:

      During the test, disconnect all the fuel injector connectors.

      Note

      Do not crank the engine for more than 2 seconds.


      1. Remove the ignition coil from the cylinder head.

      2. Install the spark plug onto the ignition coil.

      3. Disconnect the 4 fuel injector connectors.

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

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

        OK
        Sparks jump across electrode gap.

      6. Reconnect the 4 fuel injector connectors.

      7. Install the ignition coil.


    NG

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

    OK

  7. CHECK CYLINDER COMPRESSION PRESSURE OF MISFIRING CYLINDER


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


    NG

    CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

    OK

  8. CHECK INJECTOR ASSEMBLY (POWER SOURCE)


    1. A0054KEE03
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Fuel Injector)

      Disconnect the injector assembly 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
      B10-1 - Body ground Ignition switch ON 11 to 14 V
      B11-1 - Body ground Ignition switch ON 11 to 14 V
      B12-1 - Body ground Ignition switch ON 11 to 14 V
      B13-1 - Body ground Ignition switch ON 11 to 14 V

    4. Reconnect the injector assembly connector.


    NG

    CHECK FUEL INJECTOR CIRCUIT Click here

    OK

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


    1. Disconnect the injector assembly connector.

    2. Disconnect the ECM connector.

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

      Standard Resistance (Check for open)
      Tester Connection Condition Specified Condition
      B10-2 - B39-86 (#10) Always Below 1 Ω
      B11-2 - B39-85 (#20) Always Below 1 Ω
      B12-2 - B39-84 (#30) Always Below 1 Ω
      B13-2 - B39-83 (#40) Always Below 1 Ω
      Standard Resistance (Check for short)
      Tester Connection Condition Specified Condition
      B10-2 or B39-86 (#10) - Body ground Always 10 kΩ or higher
      B11-2 or B39-85 (#20) - Body ground Always 10 kΩ or higher
      B12-2 or B39-84 (#30) - Body ground Always 10 kΩ or higher
      B13-2 or B39-83 (#40) - Body ground Always 10 kΩ or higher

    4. Reconnect the injector connector.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (INJECTOR ASSEMBLY - ECM)

    OK

  10. INSPECT ECM TERMINAL OF MISFIRING CYLINDER (#10, #20, #30 AND/OR #40 VOLTAGE)


    1. A00550JE01
      Text in Illustration
      *1

      Front view of wire harness connector

      (to ECM)

      Disconnect the ECM 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
      B39-86 (#10) - B39-46 (E01) Ignition switch ON 11 to 14 V
      B39-85 (#20) - B39-46 (E01) Ignition switch ON 11 to 14 V
      B39-84 (#30) - B39-46 (E01) Ignition switch ON 11 to 14 V
      B39-83 (#40) - B39-46 (E01) Ignition switch ON 11 to 14 V

    4. Reconnect the ECM connector.


    NG

    CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND) Click here

    OK

  11. 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

    REPLACE FUEL INJECTOR ASSEMBLY Click here

    OK

  12. CHECK INTAKE SYSTEM


    1. Check the intake system for vacuum leakage Click here.

      OK
      No leakage from intake system.

    NG

    REPAIR OR REPLACE INTAKE SYSTEM

    OK

  13. CHECK FUEL PRESSURE


    1. Check the fuel pressure Click here.


    NG

    CHECK FUEL LINE Click here

    OK

  14. READ VALUE USING INTELLIGENT TESTER (COOLANT TEMP)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

    4. Enter the following menus: Powertrain / Engine and ECT / Data List / 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 95°C (167°F and 203°F).

    NG

    REPLACE ENGINE COOLANT TEMPERATURE SENSOR Click here

    OK

  15. INSPECT MASS AIR FLOW METER


    1. Inspect the mass air flow meter Click here.


    NG

    REPLACE MASS AIR FLOW METER Click here

    OK

  16. ADJUST VALVE TIMING

    Tech Tips

    There are no marks on the cylinder head for the purpose of checking valve timing. Valve timing can only be inspected by lining up the colored links on the timing chain with the marks on the pulleys. It may be necessary to remove and re-install the chain to match up the timing marks Click here.


    NEXT

  17. CHECK WHETHER DTC OUTPUT RECURS (DTC P0300, P0301, P0302, P0303 AND/OR P0304)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

    4. Clear the DTCs Click here.

    5. Start the engine and warm it up.

    6. Switch the ECM from normal mode to check mode using the tester.

    7. Run the engine at an engine speed of 1000 rpm for 4.5 minutes.

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

    9. Read the DTCs.

      Result
      Result Proceed to
      DTC is not output A
      DTC P0300, P0301, P0302, P0303 and/or P0304 are output B

    A

    SYSTEM IS OK

    B

    REPLACE ECM Click here

  18. CHECK INTAKE SYSTEM


    1. Check the intake system for vacuum leakage Click here.

      OK
      No leakage from intake system.

    NG

    REPAIR OR REPLACE INTAKE SYSTEM

    OK

  19. CHECK FUEL PRESSURE


    1. Check the fuel pressure Click here.


    NG

    CHECK FUEL LINE Click here

    OK

  20. READ VALUE USING INTELLIGENT TESTER (COOLANT TEMP)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

    4. Enter the following menus: Powertrain / Engine and ECT / Data List / 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 95°C (167°F and 203°F).

    NG

    REPLACE ENGINE COOLANT TEMPERATURE SENSOR Click here

    OK

  21. INSPECT MASS AIR FLOW METER


    1. Inspect the mass air flow meter Click here.


    NG

    REPLACE MASS AIR FLOW METER Click here

    OK

  22. ADJUST VALVE TIMING

    Tech Tips

    There are no marks on the cylinder head 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 re-install the chain to match up the timing marks Click here.


    NEXT

  23. CHECK WHETHER DTC OUTPUT RECURS (DTC P0300, P0301, P0302, P0303 AND/OR P0304)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

    4. Clear the DTCs Click here.

    5. Start the engine and warm it up.

    6. Switch the ECM from normal mode to check mode using the tester.

    7. Run the engine at an engine speed of 1000 rpm for 4.5 minutes.

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

    9. Read the DTCs.

      Result
      Result Proceed to
      DTC is not output A
      DTC P0300, P0301, P0302, P0303 and/or P0304 are output B

    A

    SYSTEM IS OK

    B

  24. CHECK SPARK PLUG


    1. A00565NE23
      *1 Electrode Gap

      Remove the ignition coil and the spark plug of the misfiring cylinder.

    2. Measure the spark plug electrode gap.

      Maximum gap
      1.0 to 1.3 mm (0.0394 to 0.0512 in.)

    3. Check the electrode for carbon deposits.

      Recommended spark plug:
      Manufacturer Product
      DENSO SC20HR11

      Note

      If the electrode gap is larger than 1.3 mm, replace the spark plug. Do not adjust the electrode gap.

    4. Reinstall the ignition coil and the spark plug.


    NG

    REPLACE SPARK PLUG Click here

    OK

  25. CHECK FOR SPARK AND IGNITION (SPARK TEST)


    1. A0058NV

      Perform a spark test.

      CAUTION:

      During the test, disconnect all fuel injector connectors.

      Note

      Do not crank the engine for more than 2 seconds.


      1. Remove the ignition coil from the cylinder head.

      2. Install the spark plug onto the ignition coil.

      3. Disconnect the 4 fuel injector connectors.

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

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

        OK
        Sparks jump across electrode gap.

      6. Reconnect the 4 fuel injector connectors.

      7. Install the ignition coil.


    NG

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

    OK

  26. CHECK CYLINDER COMPRESSION PRESSURE OF MISFIRING CYLINDER


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


    NG

    CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

    OK

  27. CHECK INJECTOR ASSEMBLY (POWER SOURCE)


    1. A0054KEE03
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Fuel Injector)

      Disconnect the injector assembly 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
      B10-1 - Body ground Ignition switch ON 11 to 14 V
      B11-1 - Body ground Ignition switch ON 11 to 14 V
      B12-1 - Body ground Ignition switch ON 11 to 14 V
      B13-1 - Body ground Ignition switch ON 11 to 14 V

    4. Reconnect the injector assembly connector.


    NG

    CHECK FUEL INJECTOR CIRCUIT Click here

    OK

  28. CHECK HARNESS AND CONNECTOR (INJECTOR ASSEMBLY - ECM)


    1. Disconnect the injector assembly connector.

    2. Disconnect the ECM connector.

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

      Standard Resistance (Check for open)
      Tester Connection Condition Specified Condition
      B10-2 - B39-86 (#10) Always Below 1 Ω
      B11-2 - B39-85 (#20) Always Below 1 Ω
      B12-2 - B39-84 (#30) Always Below 1 Ω
      B13-2 - B39-83 (#40) Always Below 1 Ω
      Standard Resistance (Check for short)
      Tester Connection Condition Specified Condition
      B10-2 or B39-86 (#10) - Body ground Always 10 kΩ or higher
      B11-2 or B39-85 (#20) - Body ground Always 10 kΩ or higher
      B12-2 or B39-84 (#30) - Body ground Always 10 kΩ or higher
      B13-2 or B39-83 (#40) - Body ground Always 10 kΩ or higher

    4. Reconnect the injector connector.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (INJECTOR ASSEMBLY - ECM)

    OK

  29. INSPECT ECM TERMINAL OF MISFIRING CYLINDER (#10, #20, #30 AND/OR #40 VOLTAGE)


    1. A00550JE01
      Text in Illustration
      *1

      Front view of wire harness connector

      (to ECM)

      Disconnect the ECM 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
      B39-86 (#10) - B39-46 (E01) Ignition switch ON 11 to 14 V
      B39-85 (#20) - B39-46 (E01) Ignition switch ON 11 to 14 V
      B39-84 (#30) - B39-46 (E01) Ignition switch ON 11 to 14 V
      B39-83 (#40) - B39-46 (E01) Ignition switch ON 11 to 14 V

    4. Reconnect the ECM connector.


    NG

    CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND) Click here

    OK

  30. 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.


    OK

    REPLACE ECM Click here

    NG

    REPLACE FUEL INJECTOR ASSEMBLY Click here

  31. 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:

      During the test, disconnect all injector connectors.

      Note

      Do not crank the engine for more than 2 seconds.


      1. Install the spark plug onto the ignition coil.

      2. Disconnect the 4 fuel injector connectors.

      3. Touch the spark plug assembly to cylinder head.

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

        OK
        Sparks jump across electrode gap.

    OK

    REPLACE SPARK PLUG Click here

    NG

  32. 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 the injector connectors.

      Note

      Do not crank the engine for more than 2 seconds.


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

      2. Disconnect the fuel injector connectors.

      3. Ground the spark plug.

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

      OK
      Sparks jump across electrode gap.

    OK

    REPLACE IGNITION COIL Click here

    NG

    REPLACE ECM Click here

  33. CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND)


    1. A0056KPE01
      Text in Illustration
      *1

      Front view of wire harness connector

      (to ECM)

      Disconnect the ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B39-46 (E01) - Body ground Always Below 1 Ω
      B39-45 (E02) - Body ground Always Below 1 Ω

    OK

    REPLACE INJECTOR ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - BODY GROUND)

  34. CHECK FUEL LINE


    1. Check the fuel lines for leaks or blockage Click here.


    OK

    REPLACE FUEL PUMP Click here

    NG

    REPAIR OR REPLACE FUEL LINE