Code No. P0300: Random/Multiple Cylinder Misfire Detected




OPERATION



  • Refer to Code No. P0201: No. 1 injector system .
  • Refer to Code No. P0202: No. 2 injector system .
  • Refer to Code No. P0203: No. 3 injector system .
  • Refer to Code No. P0204: No. 4 injector system .
  • Refer to Code No. P0205: No. 5 injector system .
  • Refer to Code No. P0206: No. 6 injector system .

FUNCTION



  • If a misfire occurs while the engine is running, the engine speed changes for an instant.
  • The engine-A/T-ECU checks for such changes in engine speed.

TROUBLE JUDGMENT


Check Conditions
  • Engine speed is 440 - 4,500 r/min.
  • Engine coolant temperature and intake air temperature are -10°C or higher.
  • Barometric pressure is 106 kPa or lower.
  • Volumetric efficiency is between 15 % and 100 %.
  • Adaptive learning is complete for the vane which generates a crankshaft position signal.
  • While the engine is running, excluding gear shifting, deceleration, sudden acceleration/deceleration and A/C compressor switching.
  • The throttle deviation is -0.06 V/10 ms to +0.06 V/10 ms.
Judgment Criterion (change in the angular acceleration of the crankshaft is used for misfire detection).
  • Misfire has occurred more frequently than the limit during the last 200 revolutions (when the catalyst temperature has been 950°C or higher).
    or
  • The misfire ratio goes beyond the permitted limit within the last 1,000 revolutions from when the exhaust gas exceeds the regulation value.

PROBABLE CAUSES



  • Included air due to lack of fuel
  • Ignition system related part(s) failed
  • Failed crank angle sensor
  • Incorrect air-fuel ratio
  • Low compression pressure
  • Failed engine coolant temperature sensor
  • Skipping of timing belt teeth.
  • Exhaust gas recirculation system and exhaust gas recirculation valve failed
  • Failed engine-A/T-ECU

DIAGNOSIS PROCEDURE

STEP 1. Check whether air is included due to the lack of fuel or not

  • Check whether users have experienced the lack of fuel or not.

Q. Has the user ever experienced the lack of fuel?
Erase the diagnosis codes to finish the check.
Go to Step 2 .

STEP 2. M.U.T.-III data list



  • Refer to Data List Reference Table .

  1. Item 02: Crank angle sensor

Q. Is the check result normal?
Go to Step 3 .
Check crank angle sensor system (Refer to Code No. P0335 ).

STEP 3. M.U.T.-III data list

  • Refer to Data List Reference Table .

  1. Item 06: Engine coolant temperature sensor
  2. Item 26: Long-term fuel compensation 1
  3. Item 27: Long-term fuel compensation 2
  4. Item 28: Short-term fuel compensation 1
  5. Item 29: Short-term fuel compensation 2

Q. Are the check results normal?
Go to Step 4 .
Perform the diagnosis code classified check procedure for the sensor that has shown an abnormal data valve (Refer to Inspection Chart for Diagnosis Code ).

STEP 4. Visual check of ignition spark.

  • Remove the spark plug and install it to the ignition coil.
  • Connect the ignition coil connector.
  • Disconnect all injector connector.
  • At the engine start, check each spark plug produces a spark.

Q. Is the check result normal?
Go to Step 6 .
Go to Step 5 .

STEP 5. Check spark plug.

  • Check spark plug itself (Refer to GROUP 16 - Ignition System <6G7> - On-vehicle Service - Spark Plug Check and Cleaning ).

Q. Is the check result normal?
Check ignition circuit system (Refer to Inspection Procedure 26 ).
Replace spark plug.

STEP 6. Connector check: Injector connector

  1. B-119 (No. 1 injector connector)
  2. B-111 (No. 2 injector connector)
  3. B-120 (No. 3 injector connector)
  4. B-105 (No. 4 injector connector)
  5. B-121 (No. 5 injector connector)
  6. B-104 (No. 6 injector connector)

Q. Are the check results normal?
Go to Step 7 .
Repair or replace the connector.

STEP 7. Check injector itself.



  • Check injector itself (Refer to ).

Q. Is the check result normal?
Go to Step 8 .
Replace the injector.

STEP 8. Fuel pressure measurement.

  • Fuel pressure measurement (Refer to )

Q. Is the check result normal?
Go to Step 9 .
Repair.

STEP 9. Check for intake of air from intake hose and inlet manifold.

Q. Is the check result normal?
Go to Step 10 .
Repair.

STEP 10. Check for skipped timing belt teeth.

Q. Is the check result normal?
Go to Step 11 .
Repair.

STEP 11. Check exhaust gas recirculation control solenoid valve itself.

  • Check exhaust gas recirculation control solenoid valve itself (Refer to GROUP 17 - Emission Control <6G7> - Exhaust Gas Recirculation (EGR) Valve - EGR Control Solenoid Valve Check <6G72> ).

Q. Is the check result normal?
Go to Step 12 .
Replace the exhaust gas recirculation control solenoid valve.

STEP 12. Check exhaust gas recirculation valve itself.

  • Check exhaust gas recirculation valve itself (Refer to GROUP 17 - Emission Control <6G7> - Exhaust Gas Recirculation (EGR) Valve - EGR Valve Check <6G72> ).

Q. Is the check result normal?
Go to Step 13 .
Replace the exhaust gas recirculation valve.

STEP 13. Check compression pressure.

  • Check compression pressure (Refer to GROUP 11E - On-vehicle Service - Compression Pressure Check ).

Q. Is the check result normal?
Go to Step 14 .
Repair the compression pressure.

STEP 14. Check the trouble symptoms.

Q. Does trouble symptom persist?
Replace the engine-ECU <M/T> or engine-A/T-ECU <A/T>.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).