P0301
2ZR-FE ENGINE CONTROL: SFI SYSTEM: P0300-P0304: 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
DESCRIPTION
When the engine misfires, high concentrations of hydrocarbons (HC) enter the exhaust gas. High HC concentration levels can cause an increase in exhaust emission levels. Extremely high concentrations of HC 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 rate. 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 (CMP) sensor and the Crankshaft Position (CKP) 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 sets a DTC.
When DTCs for misfiring cylinders are randomly set, but DTC P0300 is not set, it indicates that misfires have been detected in different cylinders at different times. DTC P0300 is only set 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 control system performance 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 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).
HINT
If a catalyst damage misfire occurs, the monitor informs the driver by blinking the MIL (1 trip).
- 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.
Misfire Monitor for Mexico Models
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 1000 misfires per 1000 crankshaft revolutions) occurs once.
An excessive misfiring rate (approximately 500 misfires per 1000 crankshaft revolutions) occurs a total of 4 times.
The ECM flashes the MIL and sets a DTC when the following condition, which could cause the Three-Way Catalytic Converter (TWC) 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 Damaging Misfire (MIL Blinks)
FOR MEXICO MODELS:
Misfire: for Mexico models
Monitor period of emission-related-misfire: for Mexico models
Monitor period of catalyst-damaged-misfire (MIL blinks): for Mexico models
TYPICAL MALFUNCTION THRESHOLDS
Monitor Period of Emission Related Misfire
Monitor Period of Catalyst Damaging Misfire (MIL Blinks)
FOR MEXICO MODELS:
Monitor period of emission-related-misfire: for Mexico models
Monitor period of catalyst-damaged-misfire (MIL blinks): for Mexico models
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 operation) 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 #4 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 rpm 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 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.
WIRING DIAGRAM
Refer to DTC P0102 P0102.
INSPECTION PROCEDURE
HINT
* Check the "Fuel Cut Elps Time" in the Data List or the Freeze Frame Data.
If the elapsed time is over 0 seconds, then the engine rotation speed is high (engine speed at which fuel cut occurs + 500 rpm).
When this has happened, there is the possibility that the valve rocker arm will become loose and a fire could start, so check that the valve rocker arm is properly attached Components.
* By clearing the DTC, "Fuel Cut Elps Time" will be cleared.
* 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 be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
* 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 in the tank.
(2) Improper fuel is used.
(3) The spark plugs have been contaminated.
(4) The problem requires further diagnosis.
* After finishing repairs, check the misfire counts of the cylinders Cylinder #1 Misfire Count to Cylinder #4 Misfire Count.
* Be sure to confirm that no misfiring cylinder DTCs are set again by conducting the confirmation driving pattern after finishing repairs.
* When one of Short FT #1 or Long FT #1 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 misfire have occurred only while warming up the engine.
* An extremely imbalanced drive wheel which causes body vibration may cause misfire DTCs detected.
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 and ECT / Trouble Codes.
(e) Read the DTCs.
Result:
HINT
If any DTCs other than P0300, P0301, P0302, P0303 and P0304 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 connected.
OK:
PCV hose is connected correctly 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 ignition switch to ON.
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Engine and ECT / 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 and ECT / Data List / Catalyst OT MF F/C.
(e) Read the value displayed on the Techstream.
Result:
B -- READ VALUE USING TECHSTREAM (CYLINDER #1, #2, #3 AND #4 MISFIRE COUNT)
A -- Continue to next step.
5. PERFORM ACTIVE TEST USING TECHSTREAM (PROHIBIT THE CATALYST OT MISFIRE PREVENT 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 and ECT / 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, #2, #3 AND #4 MISFIRE COUNT)
(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) Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Cylinder #1 (to #4) Misfire Count.
(f) Allow the engine to idle.
(g) Read each value for Cylinder #1 (to #4) 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 (for automatic transaxle models).
(2) Drive the vehicle (for manual transaxle models).
(3) Check Cylinder #1 (to #4) Misfire Count.
(4) If misfire counts are still not displayed, perform procedure "A" and "B", and then check the misfire counts again (for automatic transaxle models).
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 #4) 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 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 misfiring cylinder Testing and Inspection.
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:
Always disconnect all injector connectors.
NOTICE:
Do not crank the engine for more than 2 seconds.
OK:
Sparks jump across electrode gap.
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 (POWER SOURCE) Component Tests and General Diagnostics
NG -- GO TO FUEL INJECTOR CIRCUIT Component Tests and General Diagnostics
OK -- Continue to next step.
11. CHECK HARNESS AND CONNECTOR (ECM - FUEL INJECTOR) Component Tests and General Diagnostics
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - FUEL INJECTOR)
OK -- Continue to next step.
12. CHECK FUEL INJECTOR OF MISFIRING CYLINDER
(a) Check the injector injection (whether fuel volume is high or low, and whether injection pattern is poor) Testing and Inspection.
NG -- REPLACE FUEL INJECTOR Removal
OK -- Continue to next step.
13. CHECK INTAKE SYSTEM
(a) Check the intake system for vacuum leaks Intake System.
OK:
No leaks in intake system.
NG -- REPAIR OR REPLACE INTAKE SYSTEM Components
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 Removal
OK -- Continue to next step.
16. READ VALUE USING TECHSTREAM (MAF)
(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 and ECT / 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 5 gm/sec and 10 gm/sec (Shift lever: Neutral; A/C: Off).
NG -- CHECK HARNESS AND CONNECTOR
OK -- Continue to next step.
17. ADJUST VALVE TIMING P0011
NEXT -- Continue to next step.
18. 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 the 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 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 and ECT / Utility / All Readiness.
(j) Input the DTC: P0300, P0301, P0302, P0303 or P0304.
(k) Check the DTC judgment result.
Result:
B -- CHECK HARNESS AND CONNECTOR
A -- END
19. CHECK INTAKE SYSTEM
(a) Check the intake system for vacuum leaks Intake System.
OK:
No leaks in intake system.
NG -- REPAIR OR REPLACE INTAKE SYSTEM Components
OK -- Continue to next step.
20. CHECK FUEL PRESSURE
(a) Check the fuel pressure Fuel System.
NG -- CHECK FUEL LINE
OK -- Continue to next step.
21. READ VALUE USING TECHSTREAM (COOLANT TEMP) P0171
NG -- REPLACE ENGINE COOLANT TEMPERATURE SENSOR Removal
OK -- Continue to next step.
22. READ VALUE USING TECHSTREAM (MAF)
(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 and ECT / 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 5 gm/sec and 10 gm/sec (Shift lever: Neutral; A/C: Off).
NG -- CHECK HARNESS AND CONNECTOR
OK -- Continue to next step.
23. INSPECT SPARK PLUG
(a) Inspect the spark plug of misfiring cylinder Testing and Inspection.
NG -- REPLACE SPARK PLUG Removal
OK -- Continue to next step.
24. CHECK FOR SPARKS AND IGNITION
(a) Perform a spark test Testing and Inspection.
CAUTION:
Always disconnect all injector connectors.
NOTICE:
Do not crank the engine for more than 2 seconds.
OK:
Sparks jump across electrode gap.
NG -- CHANGE TO NORMAL SPARK PLUG AND CHECK SPARK OF MISFIRING CYLINDER
OK -- 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) Component Tests and General Diagnostics
NG -- GO TO FUEL INJECTOR CIRCUIT Component Tests and General Diagnostics
OK -- Continue to next step.
27. CHECK HARNESS AND CONNECTOR (ECM - FUEL INJECTOR) Component Tests and General Diagnostics
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - FUEL INJECTOR)
OK -- Continue to next step.
28. CHECK FUEL INJECTOR OF MISFIRING CYLINDER
(a) Check the injector injection (whether fuel volume is high or low, and whether injection pattern is poor) Testing and Inspection.
NG -- REPLACE FUEL INJECTOR Removal
OK -- Continue to next step.
29. ADJUST VALVE TIMING P0011
NEXT -- Continue to next step.
30. 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 the 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 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 and ECT / Utility / All Readiness.
(j) Input the DTC: P0300, P0301, P0302, P0303 or P0304.
(k) Check the DTC judgment result.
Result:
B -- END
A -- Continue to next step.
31. CHECK HARNESS AND CONNECTOR
(a) Check the connection and terminal contact pressure of connectors and wire harness between the mass air flow meter and ECM Electronic Circuit Inspection Procedure.
HINT
Repair any problems.
NEXT -- Continue to next step.
32. 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 the 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 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 and ECT / Utility / All Readiness.
(j) Input the DTC: P0300, P0301, P0302, P0303 or P0304.
(k) Check the DTC judgment result.
Result:
B -- END
A -- Continue to next step.
33. 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 (MASS AIR FLOW METER - ECM)
OK -- Continue to next step.
34. REPLACE MASS AIR FLOW METER
(a) Replace the mass air flow meter Removal.
HINT
If the results of the inspections performed in steps 16 and 22 indicated no problem, proceed to the next step without replacing the mass air flow meter.
NEXT -- Continue to next step.
35. 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 and wait for at least 30 seconds.
(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 and ECT / Utility / All Readiness.
(j) Input the DTC: P0300, P0301, P0302, P0303 or P0304.
(k) Check the DTC judgment result.
Result:
B -- REPLACE ECM Removal
A -- END
36. CHANGE TO NORMAL SPARK PLUG AND CHECK SPARK OF MISFIRING CYLINDER
(a) Change the installed spark plug to a good 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.
OK:
Sparks jump across electrode gap.
NG -- CHANGE TO NORMAL IGNITION COIL ASSEMBLY AND CHECK SPARK OF MISFIRING CYLINDER
OK -- REPLACE SPARK PLUG Removal
37. CHANGE TO NORMAL IGNITION COIL ASSEMBLY 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 Testing and Inspection.
CAUTION:
Always disconnect all injector connectors.
NOTICE:
Do not crank the engine for more than 2 seconds.
OK:
Sparks jump across electrode gap.
NG -- REPLACE ECM Removal
OK -- REPLACE IGNITION COIL ASSEMBLY Removal
38. CHECK FUEL LINE
(a) Check the fuel lines for leaks or blockage.
NG -- REPAIR OR REPLACE FUEL LINE
OK -- REPLACE FUEL PUMP Removal