Code No. P0300: Random/Multiple Cylinder Misfire Detected <Vehicles except for Brazil>

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-ECU <M/T> or engine-A/T-ECU <A/T> 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 first 1,000 revolutions from when the exhaust gas exceeds the regulation value.

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-ECU <M/T> or engine-A/T-ECU <A/T>

DIAGNOSIS PROCEDURE

STEP 1.M.U.T.-III data list

Item 02: Crank angle sensor

OK: Keep the engine speed constant to make the pulse width of output waveform constant.

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 .

Item 06: Engine coolant temperature sensor
Item 26: Long-term fuel compensation 1
Item 27: Long-term fuel compensation 2
Item 28: Short-term fuel compensation 1
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. Visual check of ignition spark.

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

Q. Is the check result normal?

	Go to Step 5 .

	Go to Step 4 .

STEP 4. Check spark plug.

Check spark plug (Refer to GROUP 16 - Ignition System - 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 5. Connector check: Injector connector

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

Q. Are the check results normal?

	Go to Step 6 .

	Repair or replace the connector.

STEP 6. Check injector itself.

Check Injector itself (Refer to ).

Q. Is the check result normal?

	Go to Step 7 .

	Replace the injector.

STEP 7. Fuel pressure measurement.

Fuel pressure measurement (Refer to Fuel Pressure Test )

Q. Is the check result normal?

	Go to Step 8 .

	Repair.

STEP 8. Check for intake of air from intake hose and inlet manifold.

Q. Is the check result normal?

	Go to Step 9 .

	Repair.

STEP 9. Check for skipped timing belt teeth.

Q. Is the check result normal?

	Go to Step 10 .

	Repair.

STEP 10. 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 11 .

	Replace the exhaust gas recirculation valve (stepper motor)

STEP 11. 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 ).