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

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 VVT sensor and the crankshaft position sensor. The VVT 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.

A004H37E25
Reference
*1 Fire
*2 Normal Crankposition Signal
*3 Misfire
*4 Abnormal Crankposition Signal
DTC No. DTC Detection Condition Trouble Area
P0300

Simultaneous misfiring of several cylinders occurs and one of the following conditions is met (2 trip detection logic):


  • A misfire occurs that may damage the three-way catalytic converter (MIL blinks).

  • An emission deterioration misfire occurs (MIL illuminates).

  • Open or short in engine wire harness

  • Connector connection

  • Vacuum hose connections

  • Ignition system

  • Fuel injector assembly (for port injection)

  • Fuel injector assembly (for direct injection)

  • Fuel pressure (low pressure side)

  • Fuel pressure (high pressure side)

  • Mass air flow meter

  • Engine coolant temperature sensor

  • Compression pressure

  • Valve timing

  • PCV valve and hose

  • PCV hose connections

  • Intake system

  • ECM
P0301

Misfiring of the No. 1 cylinder occurs and one of the following conditions is met (2 trip detection logic):


  • A misfire occurs that may damage the three-way catalytic converter (MIL blinks).

  • An emission deterioration misfire occurs (MIL illuminates).
P0302

Misfiring of the No. 2 cylinder occurs and one of the following conditions is met (2 trip detection logic):


  • A misfire occurs that may damage the three-way catalytic converter (MIL blinks).

  • An emission deterioration misfire occurs (MIL illuminates).
P0303

Misfiring of the No. 3 cylinder occurs and one of the following conditions is met (2 trip detection logic):


  • A misfire occurs that may damage the three-way catalytic converter (MIL blinks).

  • An emission deterioration misfire occurs (MIL illuminates).
P0304

Misfiring of the No. 4 cylinder occurs and one of the following conditions is met (2 trip detection logic):


  • A misfire occurs that may damage the three-way catalytic converter (MIL blinks).

  • An emission deterioration misfire occurs (MIL illuminates).

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


The ECM flashes the MIL and stores a DTC when either one of the following conditions, which could cause damage to the three-way catalytic converter, is detected (2 trip detection logic).


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 DTCs (even if no DTCs are stored, perform the Clear DTC procedure) Click here.

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

  7. Read the misfire counts 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.

  8. Drive the vehicle so that the vehicle conditions displayed in Engine Speed and Calculate 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, confirm the Misfire RPM and Misfire Load in the Data List.

    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 output 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 are cleared.

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

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

  12. Clear DTCs (even if no DTCs are stored, perform the Clear DTC procedure) Click here.

CAUTION / NOTICE / HINT

Tech Tips


  • 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, 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 was 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 #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 #1 or Long FT #1 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 have occurred only while warming up the engine.

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

Note

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

PROCEDURE


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


    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 / Trouble Codes.

    5. Read DTCs.

      Result
      Result Proceed to
      DTC P0300, P0301, P0302, P0303 and/or P0304 are output A
      DTC 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 valve and hose are correctly connected and are not damaged.

    NG

    REPAIR OR REPLACE PCV HOSE

    OK

  3. READ VALUE USING GTS (PORT INJECTION)


    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 / Active Test / Control the Injection Way / Port.

    5. Start the engine and allow the engine to idle.

    6. Read the Cylinder #1 Misfire Count to Cylinder #4 Misfire Count or DTCs displayed on the GTS.

      Result
      Misfire Count Proceed to
      Most misfires occur in only 1 or 2 cylinders A
      3 cylinders or more have equal misfire counts A
      There are no misfire counts B

    B

    READ VALUE USING GTS (CYLINDER MISFIRE COUNT) Click here

    A

  4. READ VALUE USING GTS (DIRECT INJECTION)


    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 / Active Test / Control the Injection Way / Direct.

    5. Start the engine and allow the engine to idle.

    6. Read the Cylinder #1 Misfire Count to Cylinder #4 Misfire Count or DTCs displayed on the GTS.

      Result
      Misfire Count Proceed to
      Port Direct
      Most misfires occur in only 1 or 2 cylinders Most misfires occur in only 1 or 2 cylinders A
      3 cylinders or more have equal misfire counts 3 cylinders or more have equal misfire counts B
      Most misfires occur in only 1 or 2 cylinders There are no misfire counts C
      3 cylinders or more have equal misfire counts There are no misfire counts D

    B

    CHECK INTAKE SYSTEM Click here

    C

    REPLACE FUEL INJECTOR ASSEMBLY (FOR PORT INJECTION) Click here

    D

    CHECK FUEL PRESSURE (LOW PRESSURE SIDE) Click here

    A

  5. INSPECT SPARK PLUG


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


    NG

    REPLACE SPARK PLUG Click here

    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.


    NEXT

  7. CHECK CYLINDER COMPRESSION PRESSURE


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


    OK

    REPLACE ECM Click here

    NG

    CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

  8. CHECK INTAKE SYSTEM


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

      OK
      No leaks from intake system.

    NG

    REPAIR OR REPLACE INTAKE SYSTEM

    OK

  9. 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 / 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 and 100°C (167 and 212°F)

    NG

    REPLACE ENGINE COOLANT TEMPERATURE SENSOR Click here

    OK

  10. 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. Start the engine.

    5. Enter the following menus: Powertrain / Engine / Data List / MAF, Coolant Temp and Engine Speed.

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

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

      Standard
      Between 13.0 gm/sec and 14.0 gm/sec (shift lever: N, A/C: Off).

    NG

    CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER CONNECTOR CONNECTION) Click here

    OK

  11. CHECK VALVE TIMING


    1. Check the valve timing Click here.

      Result
      Result Proceed to
      ABNORMAL A
      NORMAL B

    A

    ADJUST VALVE TIMING Click here

    B

    CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER CONNECTOR CONNECTION) Click here

  12. CHECK FUEL PRESSURE (LOW PRESSURE SIDE)


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


    OK

    REPLACE FUEL INJECTOR ASSEMBLY (FOR PORT INJECTION) Click here

    NG

  13. INSPECT FUEL PUMP ASSEMBLY


    1. Inspect the fuel pump assembly Click here.


    OK

    GO TO FUEL INJECTOR CIRCUIT Click here

    NG

    REPLACE FUEL PUMP ASSEMBLY Click here

  14. READ VALUE USING GTS (CYLINDER MISFIRE COUNT)


    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 / Active Test / Control the Injection Way / Direct.

    5. Start the engine and allow the engine to idle.

    6. Read the Cylinder #1 Misfire Count to Cylinder #4 Misfire Count or DTCs displayed on the GTS.

      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

    A

    REPLACE FUEL INJECTOR ASSEMBLY (FOR DIRECT INJECTION) Click here

    B

  15. READ VALUE USING GTS (CYLINDER MISFIRE COUNT)


    1. Connect the GTS to the DLC3.

    2. Start the engine and turn the GTS on.

    3. Clear DTCs ( Click here).

    4. Enter the following menus: Powertrain / Engine / Data List / Misfire RPM, Misfire Load, Cylinder #1 to #4 Misfire Count and Injection Way.

    5. Monitor all of the misfire count values or DTCs and Injection Way displayed on the GTS.

      Result
      Misfire counts Injection way Proceed to
      There are no misfire counts - A
      Most misfires occur in only 1 or 2 cylinders Either B
      3 cylinders or more have equal misfire counts Either C
      There are misfire counts Direct D

    A

    CHECK FOR INTERMITTENT PROBLEMS Click here

    C

    CHECK INTAKE SYSTEM Click here

    D

    REPLACE FUEL INJECTOR ASSEMBLY (FOR DIRECT INJECTION) Click here

    B

  16. INSPECT SPARK PLUG


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


    NG

    REPLACE SPARK PLUG Click here

    OK

  17. 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.


    NEXT

  18. CHECK CYLINDER COMPRESSION PRESSURE


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


    OK

    REPLACE ECM Click here

    NG

    CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

  19. CHECK INTAKE SYSTEM


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

      OK
      No leaks from intake system.

    NG

    REPAIR OR REPLACE INTAKE SYSTEM

    OK

  20. 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 / 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 and 100°C (167 and 212°F)

    NG

    REPLACE ENGINE COOLANT TEMPERATURE SENSOR Click here

    OK

  21. 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. Start the engine.

    5. Enter the following menus: Powertrain / Engine / Data List / MAF, Coolant Temp and Engine Speed.

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

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

      Standard
      Between 13.0 gm/sec and 14.0 gm/sec (shift lever: N, A/C: Off).

    NG

    CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER CONNECTOR CONNECTION) Click here

    OK

  22. CHECK VALVE TIMING


    1. Check the valve timing Click here.


    NG

    ADJUST VALVE TIMING Click here

    OK

  23. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER CONNECTOR CONNECTION)


    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

  24. CHECK WHETHER DTC OUTPUT RECURS


    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. Turn the ignition switch to ON.

    7. Turn the GTS on.

    8. Start the engine.

    9. Warm up the engine.

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

    11. Enter the following menus: Powertrain / Engine / Utility / All Readiness.

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

    13. Check the DTC judgment result.

      Result
      Result Proceed to

      ABNORMAL

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

      		 A

      NORMAL

      (No DTC output)

      		 B

    B

    END

    A

  25. 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 (Check for open)
      Tester Connection Condition Specified Condition
      A33-12 (THA) - C16-1 (THA) Always Below 1 Ω
      A36-29 (E1) - C16-2 (E2) Always Below 1 Ω
      Standard Resistance (Check for short)
      Tester Connection Condition Specified Condition
      A33-12 (THA) or C16-1 (THA) - Body ground Always 10 kΩ or higher
      A36-29 (E1) or C16-2 (E2) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  26. REPLACE MASS AIR FLOW METER


    1. Replace the mass air flow meter Click here.

      Tech Tips

      If the results of the inspections performed in steps 15 and 20 indicated no problem, proceed to the next step without replacing the mass air flow meter.


    NEXT

  27. CHECK WHETHER DTC OUTPUT RECURS


    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. Turn the ignition switch to ON.

    7. Turn the GTS on.

    8. Start the engine.

    9. Warm up the engine.

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

    11. Enter the following menus: Powertrain / Engine / Utility / All Readiness.

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

    13. Check the DTC judgment result.

      Result
      Result Proceed to

      NORMAL

      (No DTC output)

      		 A

      ABNORMAL

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

      		 B

    A

    END

    B

    REPLACE ECM Click here