DTC    P0300    Random / Multiple Cylinder Misfire Detected

DTC    P0301    Cylinder 1 Misfire Detected

DTC    P0302    Cylinder 2 Misfire Detected

DTC    P0303    Cylinder 3 Misfire Detected

for Preparation Click here


DESCRIPTION

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 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)
  1. Open or short in engine wire harness
  2. Connector connection
  3. Vacuum hose connections
  4. Ignition system
  5. Fuel injector assembly
  6. Fuel pressure
  7. Manifold Absolute Pressure Sensor
  8. Engine coolant temperature sensor
  9. Compression pressure
  10. Valve clearance
  11. Valve timing
  12. PCV valve and hose
  13. PCV hose connection
  14. Air induction system
  15. EGR valve assembly
  16. ECM
P0301
P0302
P0303
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


A240772E01


CONFIRMATION DRIVING PATTERN

  1. Connect an intelligent tester to the DLC3.
  2. Turn the ignition switch to ON.
  3. Turn the tester on.
  4. Record DTCs 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, #2, and #3) 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 rpm and engine load, shown in Misfire RPM and Misfire Load in the Data List.

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

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

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

    HINT:
    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 at least 5 seconds.

INSPECTION PROCEDURE

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

HINT:
  1. If any DTCs other than misfire DTCs are output, troubleshoot those DTCs first.
  2. Read freeze frame data using an 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.
  3. If the misfire does not recur when the vehicle is brought to the workshop, reproduce the conditions stored in the freeze frame data.
  4. 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.
  5. After finishing repairs, check that no misfire occurs in each cylinder (Cylinder #1, #2, and #3).
  6. Be sure to confirm that no misfiring cylinder DTCs are set again by conducting the confirmation driving pattern, after the repairs.
  7. When either Short FT #1 or Long FT #1 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).
  8. 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.
  9. An extremely imbalanced drive wheel which causes body vibration may cause misfire DTCs detection.

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

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the tester on.

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

  1. Read the DTC.

Result 
Result
Proceed to
P0300, P0301, P0302 or P0303
A
P0300, P0301, P0302 or P0303 and other DTCs
B


B
GO TO DTC CHART (Click here)
A


2.PERFORM ACTIVE TEST USING INTELLIGENT TESTER (OPERATE EGR VALVE)

  1. Connect the intelligent tester to the DLC3.

  1. Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.

    HINT:
    The A/C switch and all accessory switches should be off.

  1. Turn the intelligent tester on.

  1. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position.

  1. Check the MAP in Data List and the idling condition while performing Active Test.

    OK:
    MAP and idling condition change in response to EGR step position.


Standard:

-
EGR Step Position (Active Test)
0 Steps
0 to 30 Steps
30 to 40 Steps or Higher
Idling condition
Steady idling
Engine changes from steady to rough idling
Engine changes from rough idling to engine stall
MAP value
(Data List)
28 to 48 kPa
(EGR valve is fully closed)
MAP value is at least +10 to 15 kPa higher than when EGR valve is fully closed
80 to 110 kPa
(After engine stall)

HINT:
  1. During Active Test, if the idling condition does not change in response to EGR step position, then there is probably a malfunction in EGR valve.

Result 
Result
Proceed to
Outside standard range
A
Within standard range
B


B
Go to step 4
A


3.CHECK WHETHER DTC OUTPUT RECURS

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the tester on.

  1. Clear the DTC.

  1. Turn the ignition switch off and wait for 30 seconds.

  1. Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.

    HINT:
    The A/C switch and all accessory switches should be off.

  1. Switch the ECM from normal mode to check mode.

  1. Drive the vehicle at 60 km/h (37 mph) with the shift lever in B.

    CAUTION:
    1. Strictly observe speed limits and traffic laws when performing the confirmation drive pattern.

  1. Perform fuel-cut operation for 5 seconds or more, with the accelerator pedal fully released.

    HINT:
    1. If the deceleration was not completed, perform the confirmation driving pattern again.

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

  1. Input the DTCs to be confirmed.

  1. Check the DTC judgment result.

Result 
Result
Proceed to
No output
A
P0401
B

Intelligent Tester 
Tester Display
Description
NORMAL
  1. DTC judgment completed
  2. System normal
ABNORMAL
  1. DTC judgment completed
  2. System abnormal
INCOMPLETE
  1. DTC judgment not completed
  2. You should perform driving pattern after confirming DTC enabling conditions
UNKNOWN
  1. Unable to perform DTC judgment
  2. Number of DTCs which do not fulfill DTC preconditions has reached ECU's memory limit

HINT:
  1. If the DTC judgment result is INCOMPLETE or UNKNOWN, drive the vehicle again at 60 km/h (37 mph) with the shift lever in B, perform fuel-cut operation for 5 seconds or more with the accelerator pedal fully released, and check the DTC judgment result.



B
GO TO DTC CHART (Click here)
A


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

  1. Connect the intelligent tester to the DLC3.

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

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

  1. Read and note the Misfire RPM and Misfire Load values.

    HINT:
    The Misfire RPM and Misfire Load values indicate the vehicle conditions under which the misfire occurred.


NEXT


5.CHECK PCV HOSE (HOSE CONNECTIONS)

  1. Check the PCV hose connections (Click here).

    OK:
    PCV hose is connected correctly and is not damaged.



NG
REPAIR OR REPLACE PCV HOSE
OK


6.READ VALUE USING INTELLIGENT TESTER

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the tester on (Step "A").

  1. Enter the following menus: Powertrain / Engine / Data List / Cylinder #1 (to #3) Misfire Count (Step "B").

  1. Read each value for Cylinder #1 (to #3) Misfire Count displayed on the tester. If no misfire counts occur in any cylinders, perform the following procedure:

    1. Start the engine and let it idle.

    2. Move the shift lever to D.

    3. Check the Cylinder #1 (to #3) Misfire Count.

    4. If misfire counts are still not displayed, perform steps ("A") and ("B").

  1. Drive the vehicle while satisfying the Misfire RPM and Misfire Load values noted in the "Read Value Using Intelligent Tester (Misfire RPM and Misfire Load)" procedure above.

  1. Read Cylinder #1 (to #3) Misfire Count or the DTCs displayed on the tester.

    Result 
    Result
    		Proceed to
    Most misfires occur in only 1 or 2 cylinders
    		A
    3 cylinders or more have equal misfire counts
    		B

    HINT:
    1. 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.
    2. If the Coolant Temp value of the freeze frame data is below 75°C (167°F), the misfire may be detected only when the engine is cold.
    3. Engine Run Time value of the freeze frame data is below 120 seconds, the misfire may be detected immediately after the engine is started.



B
Go to step 19
A


7.INSPECT SPARK PLUG
A088861E08

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

  1. Measure the spark plug electrode gap.

    Maximum gap:
    1.1 mm (0.043 in.)

  1. Check the electrode for carbon deposits.
    Recommended Spark Plug 
    Manufacturer
    		Product
    DENSO
    		SK16HR11

    NOTICE:
    If the electrode gap is out of range, replace the spark plug. Do not adjust the electrode gap.

  1. Reinstall the ignition coil and the spark plug.



NG
REPLACE SPARK PLUG (Click here)
OK


8.CHECK FOR SPARKS AND IGNITION

  1. Perform a spark test.

    CAUTION:
    During the test, disconnect all of the fuel injector assembly connectors.

    NOTICE:
    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 all of the fuel injector assembly connectors.

    4. Touch the spark plug 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 all of the fuel injector assembly connectors.

    7. Reinstall the ignition coil.



NG
Go to step 31
OK


9.CHECK CYLINDER COMPRESSION PRESSURE

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



NG
CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION
OK


10.CHECK HARNESS AND CONNECTOR (FUEL INJECTOR ASSEMBLY - ECM)
A200904E01

  1. Disconnect the fuel injector assembly connectors.

  1. Disconnect the ECM connector.

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

    Standard Resistance (Check for Short):
    Tester Connection
    		Condition
    		Specified Condition
    C1-2 - B8-86 (#10)
    		Always
    		Below 1 Ω
    C2-2 - B8-85 (#20)
    		Always
    		Below 1 Ω
    C3-2 - B8-84 (#30)
    		Always
    		Below 1 Ω

    Standard Resistance (Check for Open):
    Tester Connection
    		Condition
    		Specified Condition
    C1-2 or B8-86 (#10) - Body ground
    		Always
    		10 kΩ or higher
    C2-2 or B8-85 (#20) - Body ground
    		Always
    		10 kΩ or higher
    C3-2 or B8-84 (#30) - Body ground
    		Always
    		10 kΩ or higher

    Text in Illustration 
    *1
    		Front view of wire harness connector:
    (to Fuel Injector Assembly)
    *2
    		Front view of wire harness connector:
    (to ECM)

  1. Reconnect the fuel injector assembly connectors.

  1. Reconnect the ECM connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


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


    A136305E91

  1. Disconnect the ECM connector.

  1. Turn the ignition switch to ON.

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

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    B8-86 (#10) - B8-46 (E01)
    		Ignition switch ON
    		11 to 14 V
    B8-85 (#20) - B8-46 (E01)
    		Ignition switch ON
    		11 to 14 V
    B8-84 (#30) - B8-46 (E01)
    		Ignition switch ON
    		11 to 14 V

    Text in Illustration 
    *1
    		Front view of wire harness connector:
    (to ECM)

  1. Reconnect the ECM connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - ECM)
OK


12.CHECK FUEL INJECTOR ASSEMBLY OF MISFIRING CYLINDER

  1. Check the fuel injector assembly injection (whether fuel volume is high or low, and whether injection pattern is poor) (Click here).



NG
REPLACE FUEL INJECTOR ASSEMBLY (Click here)
OK


13.CHECK VALVE CLEARANCE OF MISFIRING CYLINDER

  1. Check the valve clearance of misfiring cylinder (Click here).



NG
ADJUST VALVE CLEARANCE (Click here)
OK


14.CHECK AIR INDUCTION SYSTEM

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

    OK:
    No leaks in intake system.



NG
REPAIR OR REPLACE AIR INDUCTION SYSTEM
OK


15.CHECK VALVE TIMING

HINT:
Check the valve timing (Click here).



NG
ADJUST VALVE TIMING (Click here)
OK


16.CHECK FUEL PRESSURE

  1. Check the fuel pressure (Click here).



NG
CHECK AND REPLACE FUEL PUMP, PRESSURE REGULATOR, FUEL PIPE LINE AND FILTER
OK


17.READ VALUE USING INTELLIGENT TESTER (COOLANT TEMP)

  1. Connect an intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the tester on.

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

  1. Read the value.

    Standard:
    Between 80°C and 100°C (176°F and 212°F) with warm engine.



NG
REPLACE ENGINE COOLANT TEMPERATURE SENSOR (Click here)
OK


18.INSPECT MANIFOLD ABSOLUTE PRESSURE SENSOR

HINT:
Inspect the manifold absolute pressure sensor (Click here).



NG
REPLACE MANIFOLD ABSOLUTE PRESSURE SENSOR (Click here)
OK

REPLACE ECM (Click here)  

19.CHECK AIR INDUCTION SYSTEM

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

    OK:
    No leaks in intake system.



NG
REPAIR OR REPLACE AIR INDUCTION SYSTEM
OK


20.CHECK VALVE TIMING

HINT:
Check the valve timing (Click here).



NG
ADJUST VALVE TIMING (Click here)
OK


21.CHECK FUEL PRESSURE

  1. Check the fuel pressure (Click here).



NG
CHECK AND REPLACE FUEL PUMP, PRESSURE REGULATOR, FUEL PIPE LINE AND FILTER
OK


22.READ VALUE USING INTELLIGENT TESTER (COOLANT TEMP)

  1. Connect an intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the tester on.

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

  1. Read the value.

    Standard:
    Between 80°C and 100°C (176°F and 212°F) with warm engine.



NG
REPLACE ENGINE COOLANT TEMPERATURE SENSOR (Click here)
OK


23.INSPECT MANIFOLD ABSOLUTE PRESSURE SENSOR

HINT:
Inspect the manifold absolute pressure sensor (Click here).



NG
REPLACE MANIFOLD ABSOLUTE PRESSURE SENSOR (Click here)
OK


24.INSPECT SPARK PLUG


    A088861E08

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

  1. Measure the spark plug electrode gap.

    Maximum gap:
    1.1 mm (0.043 in.)

  1. Check the electrode for carbon deposits.
    Recommended Spark Plug 
    Manufacturer
    		Product
    DENSO
    		SK16HR11

    NOTICE:
    If the electrode gap is out of range, replace the spark plug. Do not adjust the electrode gap.

  1. Reinstall the ignition coil and the spark plug.



NG
REPLACE SPARK PLUG (Click here)
OK


25.CHECK FOR SPARK AND IGNITION

  1. Perform a spark test.

    CAUTION:
    During the test, disconnect all of the fuel injector assembly connectors.

    NOTICE:
    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 all of the fuel injector assembly connectors.

    4. Touch the spark plug 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 all of the fuel injector assembly connectors.

    7. Reinstall the ignition coil.



NG
Go to step 31
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 HARNESS AND CONNECTOR (FUEL INJECTOR ASSEMBLY - ECM)


    A200904E01

  1. Disconnect the fuel injector assembly connectors.

  1. Disconnect the ECM connector.

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

    Standard Resistance (Check for Short):
    Tester Connection
    		Condition
    		Specified Condition
    C1-2 - B8-86 (#10)
    		Always
    		Below 1 Ω
    C2-2 - B8-85 (#20)
    		Always
    		Below 1 Ω
    C3-2 - B8-84 (#30)
    		Always
    		Below 1 Ω

    Standard Resistance (Check for Open):
    Tester Connection
    		Condition
    		Specified Condition
    C1-2 or B8-86 (#10) - Body ground
    		Always
    		10 kΩ or higher
    C2-2 or B8-85 (#20) - Body ground
    		Always
    		10 kΩ or higher
    C3-2 or B8-84 (#30) - Body ground
    		Always
    		10 kΩ or higher

    Text in Illustration 
    *1
    		Front view of wire harness connector:
    (to Fuel Injector)
    *2
    		Front view of wire harness connector:
    (to ECM)

  1. Reconnect the fuel injector assembly connectors.

  1. Reconnect the ECM connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


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


    A136305E91

  1. Disconnect the ECM connector.

  1. Turn the ignition switch to ON.

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

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    B8-86 (#10) - B8-46 (E01)
    		Ignition switch ON
    		11 to 14 V
    B8-85 (#20) - B8-46 (E01)
    		Ignition switch ON
    		11 to 14 V
    B8-84 (#30) - B8-46 (E01)
    		Ignition switch ON
    		11 to 14 V

    Text in Illustration 
    *1
    		Front view of wire harness connector:
    (to ECM)

  1. Reconnect the ECM connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - ECM)
OK


29.CHECK FUEL INJECTOR ASSEMBLY OF MISFIRING CYLINDER

  1. Check the fuel injector assembly injection (whether fuel volume is high or low, and whether injection pattern is poor) (Click here).



NG
REPLACE FUEL INJECTOR ASSEMBLY (Click here)
OK


30.CHECK VALVE CLEARANCE OF MISFIRING CYLINDER

  1. Check the valve clearance of misfiring cylinder (Click here).



NG
ADJUST VALVE CLEARANCE (Click here)
OK

REPLACE ECM (Click here)  

31.CHANGE TO NORMAL SPARK PLUG AND CHECK SPARK OF MISFIRING CYLINDER

  1. Change the installed spark plug to a known good spark plug.

  1. Perform a spark test.

    CAUTION:
    During the test, disconnect all of the fuel injector assembly connectors.

    NOTICE:
    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 all of the fuel injector assembly connectors.

    4. Touch the spark plug 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 all of the fuel injector assembly connectors.

    7. Reinstall the ignition coil.



NG
Go to step 32
OK

REPLACE SPARK PLUG (Click here)  

32.CHANGE TO NORMAL IGNITION COIL AND CHECK SPARK OF MISFIRING CYLINDER

  1. Change the installed ignition coil to a known good ignition coil.

  1. Perform a spark test.

    CAUTION:
    During the test, disconnect all of the fuel injector assembly connectors.

    NOTICE:
    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 all of the fuel injector assembly connectors.

    4. Touch the spark plug 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 all of the fuel injector assembly connectors.

    7. Reinstall the ignition coil.



NG
REPLACE ECM (Click here)
OK

REPLACE IGNITION COIL (Click here)