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 more than -10°C.
  • Barometric pressure is less than 106 kPa.
  • Volumetric efficiency is between 15 % and 100 %.
  • The learning compensation control that absorbs the difference in the target location showing the crank position is completed.
  • During the usual operation, the amount of throttle change is small: between -0.06 V/10 ms and +0.06 V/10 ms.
Judgment Criteria (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
  • When the engine often misfires within the first 1,000 revolutions from when the exhaust gas exceeds the E-OBD regulation valve.

PROBABLE CAUSES



  • 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.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 2 .
Check crank angle sensor system (Refer to Code No. P0335 ).

STEP 2. 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 3 .
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 3. Check ignition coil spark.

Q. Is the check result normal?
Go to Step 4 .
Check ignition circuit system (Refer to Inspection Procedure 25 ).

STEP 4. 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 5 .
Repair or replace the connector.

STEP 5. Check injector itself.



  • Check Injector itself (Refer to ).

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

STEP 6. Fuel pressure measurement.

  • Fuel pressure measurement (Refer to )

Q. Is the check result normal?
Go to Step 7 .
Repair.

STEP 7. Check for intake of air from intake hose and inlet manifold.

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

STEP 8. Check for skipped timing belt teeth.

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

STEP 9. Check exhaust gas recirculation valve (stepper motor) itself.

  • Check exhaust gas recirculation valve (stepper motor) itself [Refer to GROUP 17 - Exhaust Gas Recirculation System - Exhaust Gas Recirculation Valve (Stepper Motor) Check ].

Q. Is the check result normal?
Go to Step 10.
Replace the exhaust gas recirculation valve (stepper motor)

STEP 10. M.U.T.-III diagnosis code

  • Reconfirmation of diagnosis code.

Q. Is the diagnosis code set?
Replace the engine-A/T-ECU.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).