P0302
2GR-FE ENGINE CONTROL: 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 camshaft position sensor and the crankshaft position sensor. The camshaft position 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 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 stores 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.
- 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 stores 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 speed, a catalyst damage misfire, which is monitored every 200 crankshaft revolutions, occurs once.
- At a normal engine speed, a catalyst damage misfire, which is monitored every 200 crankshaft revolutions, occurs 3 times.
HINT
If a catalyst damage misfire occurs, the ECM informs the driver by flashing the MIL.
Misfire Monitor for Mexico Models
The ECM illuminates the MIL and stores 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 332 misfires per 1000 crankshaft revolutions) occurs once.
- An excessive misfiring rate (approximately 166 misfires per 1000 crankshaft revolutions) occurs a total of 4 times.
The ECM flashes the MIL and stores a DTC when the following condition, which could cause the three-way catalytic converter damage, is detected (2 trip detection logic).
- A catalyst damage misfire, which is monitored every 200 crankshaft revolutions, occurs 3 times.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
Misfire
Monitor Period of Emission-Related-Misfire
Monitor Period of Catalyst-Damaged-Misfire (MIL blinks)
FOR MEXICO MODELS
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-Damaged-Misfire (MIL Blinks)
FOR MEXICO MODELS
Monitor Period of Emission-Related-Misfire
Monitor Period of Catalyst-Damage-Misfire (MIL Blinks)
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) Reading and Clearing Diagnostic Trouble Codes.
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 output 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 are cleared.
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 DTCs (even if no DTCs are stored, perform the Clear DTC procedure) Reading and Clearing Diagnostic Trouble Codes.
WIRING DIAGRAM
INSPECTION PROCEDURE
NOTICE:
Inspect the fuses for circuits related to this system before performing the following 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 stored again by conducting the confirmation driving pattern after finishing repairs.
* For 6 and 8 cylinder engines, the ECM intentionally does not stored the specific misfiring cylinder DTCs at high engine speed. If misfires occur only in high engine speed areas, only DTC P0300 is stored
In the event of DTC P0300 being present, perform the following operations:
(1) Clear the DTC 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 stored.
* 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 has occurred only while warming up the engine.
* An extremely imbalanced drive wheel which causes body vibration may cause misfire DTCs to be stored
PROCEDURE
1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO MISFIRE DTCS)
(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 / Trouble Codes.
(e) Read 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 Components.
OK:
PCV valve and hose are connected correctly and are 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 ignition switch to ON.
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Engine / Data List / 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 ignition switch to ON.
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Engine / Data List / Catalyst OT MF F/C.
(e) Read the value displayed on the Techstream.
Result
B -- READ VALUE USING TECHSTREAM (CYLINDER MISFIRE COUNT)
A -- Continue to next step.
5. PERFORM ACTIVE TEST USING TECHSTREAM (PROHIBIT CAT OT F/C)
(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 / 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 either idling or being revved within 3000 rpm.
NEXT -- Continue to next step.
6. READ VALUE USING TECHSTREAM (CYLINDER MISFIRE COUNT)
(a) Enter the following menus: Powertrain / Engine / Data List / Cylinder #1 Misfire Count, Cylinder #2 Misfire Count, Cylinder #3 Misfire Count, #4 Misfire Count, #5 Misfire Count and Cylinder #6 Misfire Count.
(b) Start the engine and allow the engine to idle.
(c) 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 steps (d) and (e) and then check the misfire counts again.
(d) Drive the vehicle with the Misfire RPM and Misfire Load noted in the "Read Value Using Techstream (Misfire RPM and Misfire Load)" procedures above.
(e) Read the Cylinder #1 Misfire Count to Cylinder #6 Misfire Count or DTCs displayed 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's record of the ECT 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 INTAKE SYSTEM
A -- Continue to next step.
7. INSPECT SPARK PLUG
(a) Inspect the spark plug of the misfiring cylinder Testing and Inspection.
NG -- REPLACE SPARK PLUG Removal
OK -- Continue to next step.
8. CHECK FOR SPARKS AND IGNITION (SPARK TEST)
(a) Disconnect the fuel injector assembly connector to prevent the engine from starting.
CAUTION:
Always disconnect all the fuel injector assembly connectors.
(b) Remove the ignition coil assembly from the cylinder head.
(c) Perform a spark test Testing and Inspection.
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 ECM TERMINAL VOLTAGE (#10, #20, #30, #40, #50 AND /OR #60)
(a) Disconnect the ECM connector.
(b) Turn the ignition switch to ON.
(c) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Text in Illustration
NG -- GO TO FUEL INJECTOR CIRCUIT Fuel Injector Circuit
OK -- Continue to next step.
11. CHECK FUEL INJECTOR OF MISFIRING CYLINDER
(a) Check the fuel injector 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.
12. CHECK INTAKE SYSTEM
(a) Check the intake system for vacuum leak.
OK:
No leaks from intake system.
NG -- REPAIR OR REPLACE INTAKE SYSTEM
OK -- Continue to next step.
13. CHECK FUEL PRESSURE
(a) Check the fuel pressure Fuel System.
NG -- CHECK FUEL LINE
OK -- Continue to next step.
14. READ VALUE USING TECHSTREAM (COOLANT TEMP) P0171
NG -- REPLACE ENGINE COOLANT TEMPERATURE SENSOR Removal
OK -- Continue to next step.
15. READ VALUE USING TECHSTREAM (MAF) P0171
NG -- CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER CONNECTOR CONNECTION)
OK -- Continue to next step.
16. CHECK VALVE TIMING P0011
OK -- CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER CONNECTOR CONNECTION)
NG -- ADJUST VALVE TIMING Installation
17. CHECK INTAKE SYSTEM
(a) Check the intake system for vacuum leaks
OK:
No leaks from intake system.
NG -- REPAIR OR REPLACE INTAKE SYSTEM
OK -- Continue to next step.
18. CHECK FUEL PRESSURE
(a) Check the fuel pressure Fuel System.
NG -- CHECK FUEL LINE
OK -- Continue to next step.
19. READ VALUE USING TECHSTREAM (COOLANT TEMP) P0171
NG -- REPLACE ENGINE COOLANT TEMPERATURE SENSOR Removal
OK -- Continue to next step.
20. READ VALUE USING TECHSTREAM (MAF) P0171
NG -- CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER CONNECTOR CONNECTION)
OK -- Continue to next step.
21. CHECK VALVE TIMING P0011
NG -- ADJUST VALVE TIMING Installation
OK -- Continue to next step.
22. INSPECT SPARK PLUG
(a) Remove the ignition coil assembly and the spark plug from the misfiring cylinder.
(b) Inspect the spark plug of the misfiring cylinder Testing and Inspection.
NG -- REPLACE SPARK PLUG Removal
OK -- Continue to next step.
23. CHECK FOR SPARKS AND IGNITION (SPARK TEST)
(a) Disconnect the fuel injector assembly connector to prevent the engine from starting.
CAUTION:
Always disconnect all the fuel injector assembly connectors.
(b) Remove the ignition coil assembly from the cylinder head.
(c) Perform a spark test Testing and Inspection.
NG -- CHANGE TO NORMAL SPARK PLUG AND CHECK SPARK OF MISFIRING CYLINDER
OK -- Continue to next step.
24. 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.
25. INSPECT ECM TERMINAL VOLTAGE (#10, #20, #30, #40, #50 AND /OR #60)
(a) Disconnect the ECM connector.
(b) Turn the ignition switch to ON.
(c) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Text in Illustration
NG -- GO TO FUEL INJECTOR CIRCUIT Fuel Injector Circuit
OK -- Continue to next step.
26. CHECK FUEL INJECTOR OF MISFIRING CYLINDER
(a) Check the fuel injector 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.
27. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER CONNECTOR CONNECTION)
(a) Check the connection and terminal contact pressure of connectors and wire harnesses between the mass air flow meter and ECM Electronic Circuit Inspection Procedure.
HINT
Repair any problems.
NEXT -- Continue to next step.
28. CHECK WHETHER DTC OUTPUT RECURS
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream on.
(d) Clear DTCs Reading and Clearing Diagnostic Trouble Codes.
(e) Turn the ignition switch off and wait for at least 30 seconds.
(f) Turn the ignition switch to ON.
(g) Turn the Techstream on.
(h) Start the engine.
(i) Warm up the engine.
(j) Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
(k) Enter the following menus: Powertrain / Engine / Utility / All Readiness.
(l) Input the DTC: P0300, P0301, P0302, P0303, 0304, P0305 or P0306.
(m) Check the DTC judgment result.
Result
B -- END
A -- Continue to next step.
29. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM) P0102
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
30. REPLACE MASS AIR FLOW METER
(a) Replace the mass air flow meter Removal.
HINT
If the results of the inspections performed in steps 15 and 20 indicated no problem, proceed to the next step without replacing the mass air flow meter.
NEXT -- Continue to next step.
31. 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 DTCs Reading and Clearing Diagnostic Trouble Codes.
(e) Turn the ignition switch off and wait for at least 30 seconds.
(f) Turn the ignition switch to ON.
(g) Turn the Techstream on.
(h) Start the engine.
(i) Warm up the engine.
(j) Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
(k) Enter the following menus: Powertrain / Engine / Utility / All Readiness.
(l) Input the DTC: P0300, P0301, P0302, P0303, 0304, P0305 or P0306.
(m) Check the DTC judgment result.
Result
B -- REPLACE ECM Removal
A -- END
32. 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 Testing and Inspection.
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 assembly and connect the ignition coil assembly connector.
(2) Disconnect the fuel injector assembly 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 AND CHECK SPARK OF MISFIRING CYLINDER
OK -- REPLACE SPARK PLUG Removal
33. CHANGE TO NORMAL IGNITION COIL AND CHECK SPARK OF MISFIRING CYLINDER
(a) Change the ignition coil assembly to an ignition coil assembly 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 assembly and connect the ignition coil assembly connector.
(2) Disconnect the fuel injector assembly 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
34. CHECK FUEL LINE
(a) Check the fuel lines for leaks or blockage.
NG -- REPAIR OR REPLACE FUEL LINE
OK -- REPLACE FUEL SUCTION WITH PUMP AND GAUGE TUBE ASSEMBLY Removal