P0305

4GR-FSE 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 hydrocarbons concentration levels can cause increases in exhaust emission levels. 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 these increases 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 level and could cause emission deterioration, the ECM illuminates the MIL and sets 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 and sets a DTC when either one of the following conditions, which could cause emission deterioration, is detected (2 trip detection logic).

- 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.

- After the first 1000 crankshaft revolutions, an excessive misfiring rate (approximately 20 to 60 misfires per 1000 crankshaft revolutions) occurs 4 times in sequential crankshaft revolutions.

- 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).

- In every 200 crankshaft revolutions at a high engine speed, the threshold misfiring percentage is recorded once.

- In every 200 crankshaft revolutions at a normal engine speed, the threshold misfiring percentage is recorded 3 times.

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

Misfire

Monitor Period of Emission-Related-Misfire

Monitor Period of Catalyst-Damage-Misfire (MIL Blinks)

TYPICAL MALFUNCTION THRESHOLDS

Monitor Period of Emission-Related-Misfire

Monitor Period of Catalyst-Damage-Misfire (MIL Blinks)

MONITOR RESULT

Refer to Checking Monitor Status Mode 6 Data.

WIRING DIAGRAM

Refer to DTC P0102 P0102.

Refer to DTC P0200 P0200.

CONFIRMATION DRIVING PATTERN

1. Connect the Techstream to the DLC3.

2. Turn the engine switch on (IG).

3. Turn the Techstream on.

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

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

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 (to #6) Misfire Count) with the engine idling. If any misfire count is displayed, skip the following confirmation driving pattern.

8. Drive the vehicle several times with the conditions, such as engine speed and engine load, shown in Misfire RPM and Misfire Load in the freeze frame data.

HINT
In order to store misfire DTCs, it is necessary to operate the vehicle for the period of time shown in the table below, with the engine speed and engine load the same as Misfire RPM and Misfire Load in the freeze frame data.

9. Check whether misfires have occurred by checking DTCs and freeze frame data.

HINT
Do not turn the engine 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 cleared.

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

11. Turn the engine switch off and wait for at least 5 seconds.

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

INSPECTION PROCEDURE

HINT
- If any DTCs other than misfire DTCs are output, troubleshoot those DTCs first.
- Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. 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 engines, 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 DTC Check / Clear.
(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 +/-20%, the air fuel ratio may be Rich (-20% or less) or Lean (+20% or more).
- When the Coolant Temp in the freeze frame data is less than 75°C (167°F), the misfires have occurred only while the engine is being warmed up.
- An extremely unbalanced drive wheel which causes body vibration may cause misfire DTC detection.

PROCEDURE

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

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

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

(e) Read the DTCs.

HINT
Write down the output DTCs.

Result:

HINT
If any DTCs other than P0300, P0301, P0302, P0303, P0304, P0305 and 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 the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

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

(e) 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 the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

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

(e) 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 the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

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

(e) 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 at 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 engine switch on (IG).

(c) Turn the Techstream on.

(d) Clear the DTCs DTC Check / Clear.

(e) Enter the following menus: Powertrain / Engine / Data List / All Data / Cylinder #1 (to #6) Misfire Count.

(f) Allow the engine to idle.

(g) Read each value for Cylinder #1 (to #6) Misfire Count displayed on the Techstream. If no misfire counts occur in any cylinders, perform the following procedures:

(1) Move the shift lever in D.

(2) Check Cylinder #1 (to #6) Misfire Count.

(3) If misfire counts are still not displayed, perform procedure "A" and "B", and then check the misfire counts again.

Procedure A: Drive the vehicle while satisfying the Misfire RPM and Misfire Load values noted in the "Read Value Using Techstream (Misfire RPM and Misfire Load)" procedure above.

Procedure B: Read the Cylinder #1 (to #6) Misfire Count or the DTCs output on the Techstream.

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 below 75°C (167°F), the misfire may be detected only when the engine is cold.
- If the freeze frame data's 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) Remove the ignition coil assembly and the spark plug of the misfiring cylinder.

(b) Measure the spark plug electrode gap.

Maximum Electrode Gap for Used Spark Plug:

1.4 mm (0.0551 in.)

If the gap is greater than the maximum, replace the spark plug.

Electrode Gap for New Spark Plug:

1.0 to 1.1 mm (0.0394 and 0.0433 in.)

(c) Check the electrode for carbon deposits.

Recommended Spark Plug

NOTICE:
If the electrode gap is larger than standard, replace the spark plug. Do not adjust the electrode gap.

(d) Reinstall the ignition coil assembly and the spark plug.

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

8. CHECK FOR SPARK AND IGNITION

(a) Perform a spark test Testing and Inspection.

CAUTION:
During the test, disconnect all fuel injector assembly connectors.

NOTICE:
Do not crank the engine for more than 2 seconds.

(1) Remove the ignition coil assembly from the cylinder head.

(2) Install the spark plug onto the ignition coil assembly.

(3) Disconnect the 6 fuel injector assembly connectors.

(4) Touch the spark plug to the cylinder head.

(5) Crank the engine for less than 2 seconds and check for spark.

OK:

Spark jumps across electrode gap.

(6) Reconnect the 6 fuel injector assembly connectors.

(7) Reinstall the ignition coil assembly.

NG -- CHANGE TO NORMAL SPARK PLUG AND CHECK SPARK OF MISFIRING CYLINDER
OK -- 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 OF MISFIRING CYLINDER

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

(b) Inspect the cold start injector Testing and Inspection.

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

11. CHECK AIR INDUCTION SYSTEM

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

OK:

No leaks in air induction system.

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

12. CHECK FUEL PRESSURE

(a) Check the fuel pressure for low pressure side Fuel System.

(b) Check the fuel pressure for high pressure side Fuel System.

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

13. READ VALUE USING TECHSTREAM (COOLANT TEMP)

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Data List / Coolant Temp.

(e) Read the Coolant Temp twice, when the engine is both cold and warmed up.

Standard:

With cold engine
Same as ambient temperature.

With warm engine
Between 75°C and 100°C (167°F and 212°F).

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

14. 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 and Coolant Temp.

(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 7.60 g/sec. and 11.40 g/sec. (shift lever: Neutral position, A/C: Off).

NG -- CHECK HARNESS AND CONNECTOR
OK -- Continue to next step.

15. CHECK VALVE TIMING P0011

NG -- ADJUST VALVE TIMING Reassembly

OK -- CHECK HARNESS AND CONNECTOR

16. CHECK AIR INDUCTION SYSTEM

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

OK:

No leaks in air induction system.

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

17. CHECK FUEL PRESSURE

(a) Check the fuel pressure for low pressure side Fuel System.

(b) Check the fuel pressure for high pressure side Fuel System.

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

18. READ VALUE USING TECHSTREAM (COOLANT TEMP)

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Data List / Coolant Temp.

(e) Read the Coolant Temp twice, when the engine is both cold and warmed up.

Standard:

With cold engine
Same as ambient temperature.

With warm engine
Between 75°C and 100°C (167°F and 212°F).

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

19. 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 and Coolant Temp.

(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 7.60 g/sec. and 11.40 g/sec. (shift lever: Neutral position, A/C: Off).

NG -- CHECK HARNESS AND CONNECTOR
OK -- Continue to next step.

20. CHECK VALVE TIMING P0011

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

21. INSPECT SPARK PLUG

(a) Remove the ignition coil assembly and the spark plug of the misfiring cylinder.

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

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

(a) Disconnect the E29 MAF meter connector.

(b) Disconnect the E5 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 MAF meter connector.

(e) Reconnect the ECM connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER - ECM)
OK -- Continue to next step.

28. REPLACE MASS AIR FLOW METER

(a) Replace the mass air flow meter Removal.

HINT
If the results of the inspections performed in steps 14 and 19 indicated no problem, proceed to the next step without replacing the mass air flow meter.

NEXT -- Continue to next step.

29. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Clear the DTCs DTC Check / Clear.

(e) Turn the engine switch off and wait for at least 30 seconds.

(f) Turn the engine switch on (IG) 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

30. CHANGE TO NORMAL SPARK PLUG AND CHECK SPARK OF MISFIRING CYLINDER

(a) Change the installed spark plug to a spark plug that functions normally.

(b) Perform a spark test.

CAUTION:
Always disconnect all injector connectors.

NOTICE:
Do not crank the engine for more than 2 seconds.

(1) Install the spark plug to the ignition coil and connect the ignition coil connector.

(2) Disconnect the injector connector.

(3) Ground the spark plug.

(4) Check if sparks occur while the engine is being cranked.

OK:

Sparks jump across electrode gap.

NG -- CHANGE TO NORMAL IGNITION COIL ASSEMBLY AND CHECK SPARK OF MISFIRING CYLINDER

OK -- REPLACE SPARK PLUG Removal

31. CHANGE TO NORMAL IGNITION COIL ASSEMBLY AND CHECK SPARK OF MISFIRING CYLINDER

(a) Change the ignition coil to a ignition coil that functions normally.

(b) Perform a spark test.

CAUTION:
Always disconnect all injector connectors.

NOTICE:
Do not crank the engine for more than 2 seconds.

(1) Install the spark plug into the ignition coil and connect the ignition coil connector.

(2) Disconnect the injector connector.

(3) Ground the spark plug.

(4) Check if sparks occur while the engine is being cranked.

OK:

Sparks jump across electrode gap.

NG -- REPLACE ECM Removal

OK -- REPLACE IGNITION COIL ASSEMBLY Removal