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Home >> Mitsubishi >> 2006 >> Lancer Evolution L4-2.0L DOHC Turbo >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P0300

P0300

The content of this article reflects the changes identified in TSB - 10-13-007.

DTC P0300: Random/Multiple Cylinder Misfire Detected

Random Misfire Circuit
- Refer to, DTC P0201 - P0204 Injector Circuit Malfunction.

CIRCUIT OPERATION
- Refer to, DTC P0201 - P0204 Injector Circuit Malfunction.

TECHNICAL DESCRIPTION
- If a misfire occurs while the engine is running, the engine speed changes for an instant.
- The ECM checks for such changes in engine speed.

DESCRIPTIONS OF MONITOR METHODS
- Monitor angular acceleration of crankshaft and detect malfunction when negative variation of the angular acceleration is large.

MONITOR EXECUTION
- Continuous

MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)

Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
- Not applicable

Sensor (The sensor below is determined to be normal)
- Camshaft position sensor
- Volume airflow sensor
- Engine coolant temperature sensor
- Intake air temperature sensor
- Barometric pressure sensor
- Throttle position sensor

DTC SET CONDITIONS

Logic Flow Chart:




Logic Flow Chart

Check Conditions
- Engine speed is between 500 and 7,000 r/min.
- Engine coolant temperature is higher than -10 degree C (14 degrees F).
- Intake air temperature is higher than -40 degree C (-40 degree F).
- Barometric pressure is higher than 76 kPa (22.4 in.Hg).
- Volumetric efficiency is at between 15 and 160 percent.
- 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 -0.59 volt/10 ms to +0.59 volt/10 ms.

Judgment Criteria (change in the angular acceleration of the crankshaft is used for misfire detection).
- Misfire has occurred more frequently than allowed during the last 200 revolutions [when the catalyst temperature is higher than 950 degrees C (1742 degrees F)].

or

- Misfire has occurred in 22 or more of the last 1,000 revolutions (corresponding to 1.5 times the limit of emission standard).

OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 14. OBD-II Drive Cycle Pattern Lists

TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Fuel aeration due to low fuel level.
- Ignition system related part(s) failed.
- Poor crankshaft position sensor.
- Incorrect air/fuel ratio.
- Low compression pressure.
- Skipping of timing belt teeth.
- EGR system and EGR valve failed.
- ECM failed.

DIAGNOSIS

Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991911: Main Harness B

Check whether fuel may be aerated due to low fuel level.
^ Check whether users have experienced the lack of fuel or not.

Q: Has the user ever experienced the lack of fuel?

YES: Ensure fuel level is not low, erase the DTC, and re-evaluate for misfire condition using the appropiate OBD-II Drive Cycle Procedure.

NO: Go to Step 1.

STEP 1. Using scan tool MB991958, check data list item 22: Crankshaft Position Sensor.

CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.




1. Connect scan tool MB991958 to the data link connector.
2. Start the engine and run at idle.
3. Set scan tool MB991958 to the data reading mode for item 22, Crankshaft Position Sensor.
4. Check the waveform of the crankshaft position sensor while keeping the engine speed constant.
- The pulse width should be constant.

5. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the sensor operating properly?

YES: Go to Step 2.

NO: Refer to, DTC P0335 - Crankshaft Position Sensor Circuit Malfunction.

STEP 2. Using scan tool MB991958, check data list item 81: Long-Term Fuel Trim (trim).




1. Start the engine and run at idle.
2. Set scan tool MB991958 to the data reading mode for item 81, Long-Term Fuel Trim (trim).
- The fuel trim should be between -12.5 and +12.5 when the load is 2,500 r/min (during closed loop) after the engine is warmed.

3. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the specification normal?

YES: Go to Step 3.

NO: Refer to, DTC P0171 - System too Lean , DTC P0172 - System too Rich.

STEP 3. Using scan tool MB991958, check data list item 82: Short-Term Fuel Trim (trim).




1. Start the engine and run at idle.
2. Set scan tool MB991958 to the data reading mode for item 82, Short-Term Fuel Trim (trim).
- The fuel trim should be between -20 and +20 when the load is 2,500 r/min (during closed loop) after the engine is warmed.

3. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the specification normal?

YES: Go to Step 4.

NO: Refer to, DTC P0171 - System too Lean , DTC P0172 - System too Rich.

STEP 4. Check the ignition coil spark.

1. Check each ignition coil spark.
2. Remove the intake manifold.




3. Remove the spark plug and connect to the spark plug cable.
4. Ground the spark plug side electrode securely.
- When the engine is cranked, the spark plug should spark.

Q: Did it spark?

YES: Go to Step 7.

NO: Go to Step 5.

STEP 5. Check the spark plugs.

CAUTION: Do not attempt to adjust the gap of the iridium plug. Cleaning of the iridium plug may result in damage to the iridium and platinum tips. Therefore, if carbon deposits must be removed, use a plug cleaner and complete cleaning within 20 seconds to protect the electrode. Do not use a wire brush.




1. Check the plug gap and replace if the limit is exceeded.

Standard value: 0.6 - 0.7 mm (0.024 - 0.028 inch)
Limit: 0.85 mm (0.030 inch)

Q: Is the plug gap at the standard value?

YES: Go to Step 6.

NO: Replace the faulty spark plug. Then go to Step 13.

STEP 6. Check the spark plug cable.




1. Check the cap and coating for cracks.
2. Measure the resistance.

Limit: Maximum 19 kOhms

Q: Is the measured resistance less than 19 kOhms?

YES: Refer to, INSPECTION PROCEDURE 33 - Ignition Circuit System Inspection Procedure 33.

NO: Replace the faulty spark plug cable. Then go to Step 13.

STEP 7. Check the injector.




1. Disconnect the injector connector.




2. Measure the resistance between each injector side connector terminal No.1 and No.2.

Standard value: 2 - 3 Ohms [at 20 degrees C (68 degrees F)]

Q: Is the measured resistance between 2 and 3 Ohms [at 20 degrees C (68 degrees F)]?

YES: Go to Step 8.

NO: Replace the faulty injector. Then go to Step 13.




STEP 8. Check harness connectors B-17, B-18, B-20, B-22 at injector for damage.

Q: Is the harness connector in good condition?

YES: Go to Step 9.

NO: Repair or replace the faulty injector connector. Then go to Step 13.




STEP 9. Check harness connector C-121 at ECM for damage.

Q: Is the harness connector in good condition?

YES: Go to Step 10.

NO: Repair or replace it. Then go to Step 13.

STEP 10. Check for harness damage between injector connector and ECM connector.







a. Check the harness wire between injector connector B-22 (terminal No.2) and ECM connector C-121 (terminal No.1) at No.1 cylinder.
b. Check the harness wire between injector connector B-20 (terminal No.2) and ECM connector C-121 (terminal No.9) at No.2 cylinder.
c. Check the harness wire between injector connector B-18 (terminal No.2) and ECM connector C-121 (terminal No.24) at No.3 cylinder.
d. Check the harness wire between injector connector B-17 (terminal No.2) and ECM connector C-121 (terminal No.2) at No.4 cylinder.

Q: Is the harness wire in good condition?

YES: Go to Step 11.

NO: Repair it. Then go to Step 13.

STEP 11. Check the following items.

1. Check the following items, and repair or replace the defective component.
a. Check for skipped timing belt teeth.
b. Check compression.
c. EGR valve failed.

Q: Are there any abnormalities?

YES: Repair or replace it. Then go to Step 13.

NO: Go to Step 12.

STEP 12. Replace the injector.




1. Replace the injector.
2. Carry out a test drive with the drive cycle pattern. Refer to, Diagnostic Function - OBD-II Drive Cycle - Pattern 14. OBD-II Drive Cycle Pattern Lists
3. Check the diagnostic trouble code (DTC).

Q: Is DTC P0300 set?

YES: Replace the ECM. Then go to Step 13.

NO: The inspection is complete.

STEP 13. Test the OBD-II drive cycle.

1. Carry out a test drive with the drive cycle pattern. Refer to, Diagnostic Function - OBD-II Drive Cycle - Pattern 14. OBD-II Drive Cycle Pattern Lists
2. Check the diagnostic trouble code (DTC).

Q: Is DTC P0300 set?

YES: Retry the troubleshooting.

NO: The inspection is complete.
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