SFI SYSTEM (w/ Electronic Throttle Control System), Diagnostic DTC:P0300, P0301, P0302, P0303

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

DESCRIPTION

When a misfire occurs in the engine, hydrocarbons (HC) enter the exhaust gas in high concentrations. If this HC concentration is high enough, there could be an increase in exhaust emission levels. High concentrations of HC can also cause the temperature of the Three-Way Catalytic Converter (TWC) to increase, possibly damaging the TWC. To prevent this increase in emissions and limit the possibility of thermal damage, the ECM monitors the misfire rate. When the temperature of the TWC reaches a point of thermal degradation, the ECM blinks the MIL. For monitoring misfire, the ECM uses both the camshaft position sensor and the crankshaft position sensor. The camshaft position sensor is used to identify misfiring cylinders and the crankshaft position sensor is used to measure variations in the crankshaft rotation speed. The misfire counters increments when crankshaft rotation speed variations exceed the threshold values.

If the misfiring rate exceeds the threshold and could cause emission deterioration, the ECM illuminates the MIL.

Tech Tips


  • When a misfire occurs, which results in damage to the TWC, the MIL blinks during every 200 engine revolutions.

  • For any particular 1,000 revolutions of the engine, misfiring which could result in emission deterioration is detected. This causes the MIL to illuminate.

DTC No. DTC Detection Condition Trouble Area
P0300

Misfiring of random cylinders is detected

(2 trip detection logic)

  • Open or short in engine wire harness

  • Connector connection

  • Ignition system

  • Injector

  • Fuel pressure

  • Manifold absolute pressure sensor

  • Engine coolant temperature sensor

  • Compression pressure

  • Valve clearance

  • Valve timing

  • ECM

P0301

P0302

P0303

Misfiring of each cylinder is detected

(2 trip trip detection detection logic)

  • Open or short in engine wire harness

  • Connector connection

  • Ignition system

  • Injector

  • Fuel pressure

  • Manifold absolute pressure sensor

  • Engine coolant temperature sensor

  • Compression pressure

  • Valve clearance

  • Valve timing

  • ECM

Tech Tips

These DTCs are detected when the engine idles for approximately 10 minutes after warm-up. (Misfire can be clearly checked by activating the air conditioning system.)

WIRING DIAGRAM

A01380XE01

CONFIRMATION DRIVING PATTERN

Allow the engine to idle for 10 minutes or more.

INSPECTION PROCEDURE

Tech Tips


  • If any DTCs other than the misfire DTCs are set simultaneously, first troubleshoot them.

  • If a misfire does not occur when the vehicle is brought to the workshop, a misfire can be confirmed by reproducing the condition of the freeze frame data. Also, after finishing repairs, confirm that misfires do not recur (see the confirmation driving pattern).

  • 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.

  • When either of Short FT #1 and Long FT #1 in the freeze frame data is over the range of -20 %, there is a possibility that the air-fuel ratio is becoming rich (-20 % or less) or lean (+20 % or more).

  • When Coolant Temp. in the freeze frame data is less than 75°C (167°F), there is a possibility that misfires occur only during engine warm-up.

  • If a misfire cannot be reproduced, the following reasons may apply: 1) the vehicle has a lack of fuel, 2) improper fuel is being used, and 3) the ignition plug has been contaminated.

PROCEDURE


  1. CHECK OTHER DTC OUTPUT (IN ADDITION TO P0300, P0301, P0302 OR P0303)


    1. Connect the intelligent tester to the DLC3.

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

    3. Select the following menu items: Powertrain / Engine and ECT / DTC.

    4. Read DTCs.

      Result
      Display (DTC Output) Proceed To
      P0300, P0301, P0302 and/or P0303 A
      P0300, P0301, P0302 and/or P0303 and other DTCs. B

      Tech Tips

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


    B

    GO TO DTC CHART

    A

  2. CHECK HARNESS AND CONNECTOR (CONNECTION CONDITION OF ENGINE WIRE HARNESS)


    1. Check the connection of the wire harnesses and connector.

      OK
      Connected correctly and no damage on the wire harnesses.

    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

  3. CHECK OUTPUT DTCS


    1. Connect the intelligent tester to the DLC3.

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

    3. Start the engine.

    4. On the intelligent tester, select the following menu items: Powertrain / Engine and ECT / DTC.

      Tech Tips

      Read the output DTCs and proceed to the appropriate step shown in the table below.

      Result
      Number of Misfire Cylinder DTC Proceed To
      1 DTC (other than DTC P0300) A
      2 DTCs or more (other than DTC P0300) B

    B

    CHECK VALVE TIMING Click here

    A

  4. CHECK SPARK PLUG


    1. Remove the ignition coil assembly.

    2. Remove the spark plug.

    3. Check the spark plug type.

      Supplier Type
      DENSO K20HR - U11
    4. A0137CAE01

      Check the spark plug electrode gap.

      Standard
      1.0 to 1.1 mm (0.039 to 0.043 in.)
      Maximum
      1.2 mm (0.047 in.)

      Note

      If adjusting the gap of a new spark plug, bend only the ground electrode. Do not touch the tip. Never attempt to adjust the gap of a used plug.

    5. Check the electrode for carbon deposits.

    6. Perform a spark test.

      CAUTION:

      Completely disconnect each injector connector.

      Note

      Do not crank the engine for more than 5 to 10 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 a spark occurs while the engine is being cranked.

        OK
        A spark jumps across the electrode gap.

    7. Reinstall the spark plug.

    8. Reinstall the ignition coil assembly.


    OK

    INSPECT ECM TERMINAL VOLTAGE (#1, #2 OR #3) Click here

    NG

  5. CHANGE NORMAL SPARK PLUG AND CHECK FOR SPARKS


    1. Replace the spark plug with the normally functioning spark plug.

    2. Perform a spark test.

      CAUTION:

      Completely disconnect each injector connector.

      Note

      Do not crank the engine for more than 5 to 10 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 a spark occurs while the engine is being cranked.

        OK
        A spark jumps across the electrode gap.

    OK

    REPLACE SPARK PLUG

    NG

  6. CHECK HARNESS AND CONNECTOR (IGNITION COIL - ECM)


    1. A0138AME07

      Disconnect the B1, B2 and/or B3 ignition coil with igniter connector.

    2. A0138OXE02

      Disconnect the B25 ECM connector.

    3. Measure the resistance.

      Standard resistance (Check for open)
      Tester Connection Specified Condition
      Ignition coil (B1-3) - IGT1 (B25-61) Below 1 Ω
      Ignition coil (B2-3) - IGT2 (B25-50) Below 1 Ω
      Ignition coil (B3-3) - IGT3 (B25-49) Below 1 Ω
      Standard resistance (Check for short)
      Tester Connection Specified Condition
      Ignition coil (B1-3) or IGT1 (B25-61) - Body ground 10 kΩ or higher
      Ignition coil (B2-3) or IGT2 (B25-50) - Body ground 10 kΩ or higher
      Ignition coil (B3-3) or IGT3 (B25-49) - Body ground 10 kΩ or higher

    4. Reconnect the ignition coil with igniter connector.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

    REPLACE IGNITION COIL W/IGNITOR

  7. INSPECT ECM TERMINAL VOLTAGE (#1, #2 OR #3)


    1. A0137XEE01

      Turn the ignition switch to ON.

    2. Measure the voltage between the terminals of the E20 ECM connector.

      Standard voltage
      Tester Connection Specified Condition
      #1 (B26-25) - E1 (B26-24) 9 to 14 V
      #2 (B26-34) - E1 (B26-24) 9 to 14 V
      #3 (B26-26) - E1 (B26-24) 9 to 14 V

    OK

    INSPECT FUEL INJECTOR (INJECTION AND INJECTION VOLUME) Click here

    NG

  8. INSPECT FUEL INJECTOR (RESISTANCE)


    1. Measure the resistance of the injector of the misfiring cylinder Click here.

      Standard Resistance
      11.6 to 12.4 Ω at 20 °C (68°F)

    NG

    REPLACE FUEL INJECTOR

    OK

  9. CHECK HARNESS AND CONNECTOR (INJECTOR - ECM, INJECTOR - EFI RELAY)


    1. A0137HCE01

      Check the harness and connectors between the injector and ECM.


      1. Disconnect the B7, B8 and/or B9 injector connectors.

      2. Disconnect the B26 ECM connector.

      3. Measure the resistance.

        Standard resistance (Check for open)
        Tester Connection Specified Condition
        Injector (B7-1) - #1 (B26-25) Below 1 Ω
        Injector (B8-1) - #2 (B26-34) Below 1 Ω
        Injector (B9-1) - #3 (B26-26) Below 1 Ω
        Standard resistance (Check for open)
        Tester Connection Specified Condition
        Injector (B7-1) or #1 (B26-25) - Body ground 10 kΩ or higher
        Injector (B8-1) or #2 (B26-34) - Body ground 10 kΩ or higher
        Injector (B9-1) or #3 (B26-26) - Body ground 10 kΩ or higher

      4. Reconnect the ECM connector.

    2. Check the harness and connectors between the injector and EFI relay.


      1. Disconnect the B7, B8 and/or B9 injector connectors.

      2. Remove the engine room R/B.

      3. Remove the engine room R/B lower cover.

      4. Measure the resistance.

        Standard resistance (Check for open)
        Tester Connection Specified Condition
        Injector (B7-2) - Engine room R/B (1C-5) Below 1 Ω
        Injector (B8-2) - Engine room R/B (1C-5) Below 1 Ω
        Injector (B9-2) - Engine room R/B (1C-5) Below 1 Ω
        Standard resistance (Check for open)
        Tester Connection Specified Condition
        Injector (B7-2) or Engine room R/B (1C-5) - Body ground 10 kΩ or higher
        Injector (B8-2) or Engine room R/B (1C-5) - Body ground 10 kΩ or higher
        Injector (B9-2) or Engine room R/B (1C-5) - Body ground 10 kΩ or higher

      5. Reconnect the injector connector.

      6. Reinstall the engine room R/B.


    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

  10. INSPECT FUEL INJECTOR (INJECTION AND INJECTION VOLUME)


    1. Measure the injection volume of the injector of the misfiring cylinder Click here.

      Standard
      47 to 58 mm3 (2.87 to 3.54 cu in.) in 15 seconds

    NG

    REPLACE FUEL INJECTOR

    OK

  11. CHECK CYLINDER COMPRESSION PRESSURE


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

      Standard
      Minimum pressure
      1,079 kPa (11.0 kgf/cm2, 156 psi)
      Difference between each cylinder
      147 kPa (1.5 kgf/cm2, 21 psi)

    NG

    CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

    OK

  12. CHECK VALVE CLEARANCE


    1. Inspect the valve clearance of the misfiring cylinder Click here.

      Standard (cold)
      Intake
      0.145 to 0.235 mm (0.00571 to 0.00925 in.)
      Exhaust
      0.275 to 0.365 mm (0.01083 to 0.01437 in.)

    NG

    ADJUST VALVE CLEARANCE

    OK

  13. CHECK OUTPUT DTC (REFER TO RESULT OF STEP 3)

    Tech Tips

    Read the output DTCs and proceed to the appropriate step shown in the table below.

    Result
    Number of Misfire Cylinder DTC Proceed To
    1 DTC (other than DTC P0300) A
    2 DTCs or more (other than DTC P0300) B

    B

    GO TO "CHECK FOR INTERMITTENT PROBLEMS"

    A

  14. CHECK VALVE TIMING


    1. Inspect the valve timing Click here.

      OK
      The matchmarks of the crankshaft pulley and camshaft pulley are aligning.

    NG

    ADJUST VALVE TIMING

    OK

  15. CHECK FUEL PRESSURE


    1. Inspect the fuel pressure Click here.

      Standard
      304 to 343 kPa (3.1 to 3.5 kgf/cm2, 44.1 to 49.7 psi)

    NG

    REPAIR OR REPLACE FUEL SYSTEM

    OK

  16. READ VALUE USING VACUUM SENSOR (INTAKE AIR TEMPERATURE AND MANIFOLD ABSOLUTE PRESSURE)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Check the intake air temperature.


      1. On the intelligent tester, select the following menu items: Powertrain / Engine and ECT / Data List / Intake Air.

      2. Read the value.

        Standard
        Equivalent to the ambient air temperature.

    4. Check the mass air flow rate.


      1. On the intelligent tester, select the following menu items: Powertrain / Engine and ECT / Data List / MAP

      2. Read the values.

        Standard
        Condition Manifold absolute pressure (kPa)
        Ignition switch ON (do not start engine) 50 to 115
        Idling 25 to 45
        Revving up without load (2,500 rpm) 20 to 45

    NG

    REPLACE MANIFOLD ABSOLUTE PRESSURE SENSOR

    OK

  17. READ VALUE USING ENGINE COOLANT TEMPERATURE SENSOR


    1. Connect the intelligent tester to the DLC3.

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

    3. Select the following menu items: Powertrain / Engine and ECT / Date List / Coolant Temp.

    4. Read the Coolant Temp. value when the engine is cold and warmed up.

      Standard
      Engine coolant temperature when the engine is cold
      Same as the ambient temperature.
      Engine coolant temperature when the engine is warmed up
      75° to 95°C (167° to 203 °F)

    NG

    REPLACE ENGINE COOLANT TEMPERATURE SENSOR

    OK

  18. CHECK OUTPUT DTCS (REFER TO RESULT OF STEP 3)

    Tech Tips

    Read the output DTCs and proceed to the appropriate step shown in the table below.

    Result
    Number of Misfire Cylinder DTC Proceed To
    1 DTC (other than DTC P0300) A
    2 DTCs or more (other than DTC P0300) B

    B

    CHECK SPARK PLUG Click here

    A

    GO TO "CHECK FOR INTERMITTENT PROBLEMS"