P0300

2GR-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0300-P0306: Random / Multiple Cylinder Misfire Detected

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

DTC P0304 - Cylinder 4 Misfire Detected

DTC P0305 - Cylinder 5 Misfire Detected

DTC P0306 - Cylinder 6 Misfire Detected

DESCRIPTION

When the engine misfires, high concentrations of hydrocarbons (HC) enter the exhaust gas. Extremely high hydrocarbon concentration levels can cause an increase in exhaust emission levels. Extremely 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 this increase in emissions and to limit the possibility of thermal damage, the ECM monitors the misfire count. 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 both the VVT sensor and the crankshaft position sensor. The VVT 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 when the crankshaft rotation speed variations exceed predetermined thresholds. If the misfire count exceeds the threshold levels, and could cause emission control system performance deterioration, the ECM illuminates the MIL and stores a DTC.

When DTCs for misfiring cylinders are randomly stored, but DTC P0300 is not stored, it indicates that misfires have been detected in different cylinders at different times. DTC P0300 is only stored when several misfiring cylinders are detected at the same time.

MONITOR DESCRIPTION

The ECM illuminates the MIL (immediate detection logic) and sets a DTC (2 trip detection logic) when either one of the following conditions, which could cause emission deterioration, is detected.

- Within the first 1000 crankshaft revolutions of the engine starting, an excessive misfiring rate (approximately 20 to 50 misfires per 1000 crankshaft revolutions) occurs once.

- An excessive misfiring rate (approximately 20 to 50 misfires per 1000 crankshaft revolutions) occurs a total of 4 times.

The ECM flashes the MIL and sets a DTC when either one of the following conditions, which could cause the three-way catalytic converter damage, is detected (2 trip detection logic).

- At a high engine rpm, a catalyst damage misfire, which monitored every 200 crankshaft revolutions, occurs once.

- At a normal engine rpm, a catalyst damage misfire, which monitored every 200 crankshaft revolutions, occurs 3 times.

HINT
If a catalyst damage misfire occurs, the ECM informs the driver by flashing the MIL.

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

Misfire

Monitor period of emission-related-misfire

Monitor period of catalyst-damaged-misfire (MIL blinks)

TYPICAL MALFUNCTION THRESHOLDS

Monitor period of emission-related-misfire:

Monitor period of catalyst-damaged-misfire (MIL blinks):

MONITOR RESULT

Refer to Checking Monitor Status Mode 6 Data.

CONFIRMATION DRIVING PATTERN

1. Connect the Techstream to the DLC3.

2. Turn the ignition switch to ON.

3. Turn the Techstream on.

4. Record the DTC(s) and freeze frame data.

5. Clear DTCs (even if no DTCs are stored, perform the clear DTC procedure).

6. Using the Techstream, switch the ECM from normal mode to check mode Check Mode Procedure.

7. Read the misfire counts of each cylinder (Cylinder #1 Misfire Count to Cylinder #6 Misfire Count) with the engine idling. If any misfire count is displayed, skip the following confirmation driving pattern.

8. Drive the vehicle so that the vehicle conditions displayed in Misfire RPM and Misfire Load of the Data List are the same as the freeze frame data. Perform this step several times.

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

9. Check whether misfires have occurred by checking 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 erased.

10. Record the DTC(s), freeze frame data and misfire counts.

11. Turn the ignition switch off and wait for at least 30 seconds.

12. Clear the DTCs (even if no DTCs are stored, perform the Clear DTC procedure).

WIRING DIAGRAM

Fuel injector assembly circuit:

Mass air flow meter circuit: Refer to DTC P0102 P0102

INSPECTION PROCEDURE

HINT
* If any DTCs other than misfire DTCs are output, troubleshoot those DTCs first.
* Read freeze frame data using Techstream. Freeze frame data records the engine condition when malfunctions are detected. 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.
* If the misfire does not recur when the vehicle is brought to the workshop, reproduce the conditions stored in the ECM as freeze frame data.
* If the misfire still cannot be reproduced even though the conditions stored in the ECM as freeze frame data have been reproduced, one of the following factors is considered to be a possible cause of the problem:
(1) There was insufficient fuel volume in the tank.
(2) Improper fuel is used.
(3) The spark plugs have been contaminated.
* After finishing repairs, check the misfire counts of the cylinders (Cylinder #1 Misfire Count to Cylinder #6 Misfire Count).
* Be sure to confirm that no misfiring cylinder DTCs are set again by conducting the confirmation driving pattern after finishing repairs.
* For 6 cylinder engine, the ECM intentionally does not set the specific misfiring cylinder DTCs at high engine speed. If misfires occur only in high engine speed areas, only DTC P0300 is set.
In the event of DTC P0300 being present, perform the following operations:
(1) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.
(2) Start the engine and conduct the confirmation driving pattern.
(3) Read the misfiring rates of each cylinder or DTC(s) using the Techstream.
(4) Repair the cylinder(s) that has a high misfiring rate or is indicated by the DTC.
(5) After finishing repairs, conduct the confirmation driving pattern again, in order to verify that DTC P0300 is not set.
* When one of Short FT #1, Long FT #1, Short FT #2 or Long FT #2 in the freeze frame data is outside the range of +/-15%, the air fuel ratio may be Rich (-15% or less) or Lean (+15% or more).
* When the Coolant Temp in the freeze frame data is less than 75°C (167°F), the misfire have occurred only while warming up the engine.
* An extremely imbalanced drive wheel which causes body vibration may cause misfire DTCs detection.

PROCEDURE

1. CHECK ANY OTHER DTCs OUTPUT (IN ADDITION TO MISFIRE CODES)

(a) Connect Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Trouble Codes.

(e) Read the DTCs.

Result:

HINT
If any DTCs other than P0300, P0301, P0302, P0303, P0304, P0305 and/or P0306 are output, troubleshoot those DTCs first.

B -- GO TO DTC CHART SFI System
A -- Continue to next step.

2. CHECK PCV HOSE CONNECTIONS

(a) Check the PCV hose connections On-Vehicle Inspection.

OK:

PCV hose is correctly connected and is not damaged.

NG -- REPAIR OR REPLACE PCV HOSE
OK -- Continue to next step.

3. READ VALUE USING TECHSTREAM (MISFIRE RPM AND MISFIRE LOAD)

(a) Connect Techstream to the DLC3.

(b) Turn the ignition switch to ON and turn the Techstream on.

(c) Enter the following menus: Powertrain / Engine / Data List / All Data / Misfire RPM and Misfire Load.

(d) 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 -- Continue to next step.

4. READ VALUE USING TECHSTREAM (CATALYST OT MF F/C)

(a) Connect Techstream to the DLC3.

(b) Turn the ignition switch to ON and turn the Techstream on.

(c) Enter the following menus: Powertrain / Engine / Data List / All Data / Catalyst OT MF F/C.

(d) Read the value displayed on the Techstream.

Result:

B -- READ VALUE USING TECHSTREAM (CYLINDER #1 (TO #6) MISFIRE COUNT)
A -- Continue to next step.

5. PERFORM ACTIVE TEST USING TECHSTREAM

(a) Connect Techstream to the DLC3.

(b) Turn the ignition switch to ON and turn the Techstream on.

(c) Enter the following menus: Powertrain / Engine / Active Test / Prohibit the Catalyst OT Misfire prevent F/C.

(d) Perform the Active Test.

NOTICE:
When performing the Active Test, make sure the vehicle is stopped and the engine is either idling or being revved within 3000 rpm or less.

NEXT -- Continue to next step.

6. READ VALUE USING TECHSTREAM (CYLINDER #1 (TO #6) MISFIRE COUNT)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Data List / Cylinder #1 Misfire Count, Cylinder #2 Misfire Count, Cylinder #3 Misfire Count, Cylinder #4 Misfire Count, Cylinder #5 Misfire Count and Cylinder #6 Misfire Count.

(e) Start the engine and allow the engine to idle.

(f) Read each value for Cylinder #1 Misfire Count to Cylinder #6 Misfire Count displayed on the Techstream. If no misfire counts occur in any cylinders, perform procedure [A] and [B] and then check the misfire counts again.

(g) Drive the vehicle with the Misfire RPM and Misfire Load noted in the "Read Value Using Techstream (Misfire RPM And Misfire Load)" procedures above [A].

(h) Read the Cylinder #1 Misfire Count to Cylinder #6 Misfire Count or DTCs displayed on the Techstream [B].

Result

HINT
* 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.
* If the freeze frame data record of the engine coolant temperature is less than 75°C (167°F), the misfire may be detected only when the engine is cold.
* If the freeze frame data record of the Engine Run Time is below 120 seconds, the misfire may be detected immediately after the engine is started.

B -- CHECK AIR INDUCTION SYSTEM
A -- Continue to next step.

7. INSPECT SPARK PLUG

(a) Inspect the spark plug of misfiring cylinder Inspection.

NG -- REPLACE SPARK PLUG
OK -- Continue to next step.

8. CHECK FOR SPARK (SPARK TEST)

(a) Perform a spark test On-Vehicle Inspection.

HINT
If the result of the spark test is normal, proceed to the next step.

NEXT -- Continue to next step.

9. CHECK CYLINDER COMPRESSION PRESSURE

(a) Measure the cylinder compression pressure of the misfiring cylinder Engine.

NG -- CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION
OK -- Continue to next step.

10. CHECK FUEL INJECTOR ASSEMBLY (POWER SOURCE)

(a) Disconnect the fuel injector assembly connector (of the misfiring cylinder).

(b) Turn the ignition switch to ON.

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

Standard Voltage:

(d) Reconnect the fuel injector assembly connector.

NG -- CHECK HARNESS AND CONNECTOR (IG2 RELAY - FUEL INJECTOR ASSEMBLY)
OK -- Continue to next step.

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

(a) Disconnect the fuel injector assembly connector.

(b) Disconnect the ECM connector.

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

Standard Resistance (Check for Open):

Standard Resistance (Check for Short):

(d) Reconnect the fuel injector assembly connector.

(e) Reconnect the ECM connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (FUEL INJECTOR ASSEMBLY - ECM)
OK -- Continue to next step.

12. CHECK FUEL INJECTOR ASSEMBLY OF MISFIRING CYLINDER

(a) Check the fuel injector assembly injection (whether fuel volume is high or low, and whether injection pattern is poor) Testing and Inspection.

NG -- REPLACE FUEL INJECTOR ASSEMBLY Removal
OK -- Continue to next step.

13. CHECK AIR INDUCTION SYSTEM

(a) Check the air induction system for vacuum leaks.

OK:

No leaks in air induction system.

NG -- REPAIR OR REPLACE AIR INDUCTION SYSTEM
OK -- Continue to next step.

14. CHECK FUEL PRESSURE

(a) Check the fuel pressure Fuel System.

NG -- CHECK FUEL LINE
OK -- Continue to next step.

15. READ VALUE USING TECHSTREAM (COOLANT TEMP) P0171

NG -- REPLACE ENGINE COOLANT TEMPERATURE SENSOR
OK -- Continue to next step.

16. READ VALUE USING TECHSTREAM (MAF)

(a) Connect the Techstream to the DLC3.

(b) Start the engine.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Data List / All Data / MAF, Coolant Temp and Engine Speed.

(e) Allow the engine to idle until Coolant Temp reaches 75°C (167°F) or higher.

(f) Read MAF with the engine speed at 3000 rpm.

Standard:

Between 12 g/sec. and 17 g/sec. (shift lever: N; A/C: Off).

NG -- CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER CONNECTOR CONNECTION)
OK -- Continue to next step.

17. CHECK VALVE TIMING P0011

OK -- CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER CONNECTOR CONNECTION)

NG -- ADJUST VALVE TIMING Reassembly

18. CHECK AIR INDUCTION SYSTEM

(a) Check the air induction system for vacuum leaks.

OK:

No leaks from air induction system.

NG -- REPAIR OR REPLACE AIR INDUCTION SYSTEM
OK -- Continue to next step.

19. CHECK FUEL PRESSURE

(a) Check the fuel pressure Fuel System.

NG -- CHECK FUEL LINE
OK -- Continue to next step.

20. READ VALUE USING TECHSTREAM (COOLANT TEMP) P0171

NG -- REPLACE ENGINE COOLANT TEMPERATURE SENSOR
OK -- Continue to next step.

21. READ VALUE USING TECHSTREAM (MAF)

(a) Connect the Techstream to the DLC3.

(b) Start the engine.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Data List / All Data / MAF, Coolant Temp and Engine Speed.

(e) Allow the engine to idle until Coolant Temp reaches 75°C (167°F) or higher.

(f) Read MAF with the engine speed at 3000 rpm.

Standard:

Between 12 g/sec. and 17 g/sec. (shift lever: N; A/C: Off).

NG -- CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER CONNECTOR CONNECTION)
OK -- Continue to next step.

22. CHECK VALVE TIMING P0011

NG -- ADJUST VALVE TIMING Reassembly
OK -- Continue to next step.

23. CHECK SPARK PLUG

(a) Inspect the spark plug of misfiring cylinder Inspection.

NG -- REPLACE SPARK PLUG
OK -- Continue to next step.

24. CHECK FOR SPARK (SPARK TEST)

(a) Perform a spark test On-Vehicle Inspection.

HINT
If the result of the spark test is normal, proceed to the next step.

NEXT -- Continue to next step.

25. CHECK CYLINDER COMPRESSION PRESSURE

(a) Measure the cylinder compression pressure of the misfiring cylinder Engine.

NG -- CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION
OK -- Continue to next step.

26. CHECK FUEL INJECTOR ASSEMBLY (POWER SOURCE)

(a) Disconnect the fuel injector assembly connector (of the misfiring cylinder).

(b) Turn the ignition switch to ON.

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

Standard Voltage:

(d) Reconnect the fuel injector assembly connector.

NG -- CHECK HARNESS AND CONNECTOR (IG2 RELAY - FUEL INJECTOR ASSEMBLY)
OK -- Continue to next step.

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

(a) Disconnect the fuel injector assembly connector.

(b) Disconnect the ECM connector.

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

Standard Resistance (Check for Open):

Standard Resistance (Check for Short):

B -- END
A -- Continue to next step.

31. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)

(a) Disconnect the mass air flow meter connector.

(b) Disconnect the ECM connector.

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

Standard Resistance (Check for Open):

Standard Resistance (Check for Short):

(d) Reconnect the mass air flow meter connector.

(e) Reconnect the ECM connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

32. REPLACE MASS AIR FLOW METER

(a) Replace the mass air flow meter.

HINT
If the results of the inspections performed in steps 16 and 21 indicated no problem, proceed to the next step without replacing the mass air flow meter.

NEXT -- Continue to next step.

33. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.

(e) Turn the ignition switch off.

(f) Turn the ignition switch to ON and turn the Techstream on.

(g) Start the engine and warm it up.

(h) Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

(i) Enter the following menus: Powertrain / Engine / Utility / All Readiness.

(j) Input the DTC: P0300, P0301, P0302, P0303, P0304, P0305 or P0306.

(k) Check the DTC judgment result.

Result

B -- REPLACE ECM Removal

A -- END

34. CHECK FUEL LINE

(a) Check the fuel lines for leaks or blockage.

NG -- REPAIR OR REPLACE FUEL LINE

OK -- REPLACE FUEL PUMP Removal

35. CHECK HARNESS AND CONNECTOR (IG2 RELAY - FUEL INJECTOR ASSEMBLY)

(a) Disconnect the fuel injector assembly connector.

(b) Remove the IG2 relay from the engine room relay block.

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

Standard Resistance (Check for Open):

Standard Resistance (Check for Short):

(d) Reinstall the IG2 relay.

(e) Reconnect the fuel injector assembly connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (IG2 RELAY - FUEL INJECTOR ASSEMBLY)

OK -- CHECK ECM POWER SOURCE CIRCUIT ECM Power Source Circuit