SFI SYSTEM, Diagnostic DTC:P0300,P0301,P0302,P0303 and P0304
| DTC Code | DTC Name |
|---|---|
| P0300 | Random / Multiple Cylinder Misfire Detected |
| P0301 | Cylinder 1 Misfire Detected |
| P0302 | Cylinder 2 Misfire Detected |
| P0303 | Cylinder 3 Misfire Detected |
| P0304 | Cylinder 4 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.
DTC No. |
Detection Item |
DTC Detection Condition |
Trouble Area |
MIL |
Memory |
|---|---|---|---|---|---|
P0300 |
Random / Multiple Cylinder Misfire Detected |
Simultaneous misfiring of several cylinders occurs and one of the following conditions is met (2 trip detection logic):
|
|
Comes on/Blinks*
|
DTC stored |
P0301 |
Cylinder 1 Misfire Detected |
Misfiring of the No. 1 cylinder occurs and one of the following conditions is met (2 trip detection logic):
|
|
Comes on/Blinks*
|
DTC stored |
P0302 |
Cylinder 2 Misfire Detected |
Misfiring of the No. 2 cylinder occurs and one of the following conditions is met (2 trip detection logic):
|
|
Comes on/Blinks*
|
DTC stored |
P0303 |
Cylinder 3 Misfire Detected |
Misfiring of the No. 3 cylinder occurs and one of the following conditions is met (2 trip detection logic):
|
|
Comes on/Blinks*
|
DTC stored |
P0304 |
Cylinder 4 Misfire Detected |
Misfiring of the No. 4 cylinder occurs and one of the following conditions is met (2 trip detection logic):
|
|
Comes on/Blinks*
|
DTC stored |
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 stores a DTC when the following condition, which could cause catalyst deterioration, is detected (2 trip detection logic).
An excessive misfiring rate (approximately 20 to 50 misfires per 1000 crankshaft revolutions) occurs a total of 4 times.
The ECM flashes the MIL (immediate detection logic) and stores a DTC (2 trip detection logic) when either one of the following conditions, which could cause damage to the three-way catalytic converter, is detected.
A sufficient amount of misfires to damage the catalyst occurring within 200 crankshaft revolutions is detected 3 times.
CONFIRMATION DRIVING PATTERN
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Record the DTC(s) and freeze frame data.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Switch the ECM from normal mode to check mode (Click here).
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.
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.
Tip:In order to store misfire DTCs, it is necessary to operate the vehicle for the period of time shown in the table below, using the Misfire RPM and Misfire Load in the Data List.
Engine Speed (rpm)
Duration
Idling
8.0 minutes or more
1000
4.5 minutes or more
2000
2.5 minutes or more
3000
1.5 minutes or more
Check whether misfires have occurred by checking DTCs and freeze frame data.
Tip: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 cleared.
Record the DTC(s), freeze frame data and misfire counts.
Turn the ignition switch off and wait for at least 30 seconds.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
WIRING DIAGRAM
Refer to DTC P0102 (Click here).
Refer to Fuel Injector Circuit (Click here).
CAUTION / NOTICE / HINT
Inspect the fuses for circuits related to this system before performing the following procedure.
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 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 (Click here).
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 GTS. 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:
-
There was insufficient fuel in the tank.
Improper fuel was used.
The spark plugs have been contaminated.
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 stored 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 +/-15%, the air fuel ratio may be rich (-15% or less) or lean (+15% or more).
When Coolant Temp in the freeze frame data is less than 75°C (167°F), the misfires have occurred only while warming up the engine.
An extremely imbalanced drive wheel which causes body vibration may cause misfire DTCs to be stored.
PROCEDURE
CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO MISFIRE DTCS)
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
Powertrain > Engine and ECT > Trouble Codes
Read the DTCs.
Result
Result
Proceed to
DTC P0300, P0301, P0302, P0303 and/or P0304 are output
A
DTC P0300, P0301, P0302, P0303 and/or P0304 and other DTCs are output
B
Tip:If any DTCs other than P0300, P0301, P0302, P0303 and P0304 are output, troubleshoot those DTCs first.
CHECK PCV HOSE CONNECTIONS
Check the PCV hose connections.
OK
PCV valve and hose are correctly connected and are not damaged.
Result
Proceed to
OK
NG
READ VALUE USING GTS (MISFIRE RPM AND MISFIRE LOAD)
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Misfire RPM and Misfire Load.
Powertrain > Engine and ECT > Data List
Tester Display
Misfire RPM
Misfire Load
Read and note the Misfire RPM and Misfire Load values.
Tip:The Misfire RPM and Misfire Load values indicate the vehicle conditions under which the misfire occurred.
Result
Proceed to
NEXT
READ GTS (CYLINDER MISFIRE COUNT)
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Cylinder #1 Misfire Count, Cylinder #2 Misfire Count, Cylinder #3 Misfire Count and Cylinder #4 Misfire Count.
Powertrain > Engine and ECT > Data List
Tester Display
Cylinder #1 Misfire Count
Cylinder #2 Misfire Count
Cylinder #3 Misfire Count
Cylinder #4 Misfire Count
Start the engine and allow the engine to idle.
Read each value for Cylinder #1 Misfire Count to Cylinder #4 Misfire Count displayed on the GTS. If no misfire counts occur in any cylinders, perform procedure [A] and [B] and then check the misfire counts again.
Drive the vehicle with the Misfire RPM and Misfire Load noted in the read value using GTS (Misfire RPM and Misfire Load) procedures above [A].
Read the Cylinder #1 Misfire Count to Cylinder #4 Misfire Count or DTCs displayed on the GTS [B].
Result
Result
Proceed to
Most misfires occur in only 1 or 2 cylinders
A
3 cylinders or more have equal misfire counts
B
Tip: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 less than 120 seconds, the misfire may be detected immediately after the engine is started.
B CHECK INTAKE SYSTEMClick here
INSPECT SPARK PLUG
Inspect the spark plug of the misfiring cylinder (Click here).
Tip:Perform "Inspection After Repair" after replacing the spark plug (Click here).
Result
Proceed to
OK
NG
CHECK FOR SPARKS (SPARK TEST)
Perform a spark test (Click here).
Tip:If the result of the spark test is normal, proceed to the next step.
Perform "Inspection After Repair" after repairing or replacing the ignition system (Click here).
Result
Proceed to
NEXT
CHECK CYLINDER COMPRESSION PRESSURE
Measure the cylinder compression pressure of the misfiring cylinder (Click here).
Tip:Perform "Inspection After Repair" after repairing or replacing the engine assembly (Click here).
Result
Proceed to
OK
NG
NG CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION
CHECK TERMINAL VOLTAGE (#10, #20, #30 AND/OR #40)
-
*a
Front view of wire harness connector
(to ECM)
Disconnect the ECM connector.
Turn the ignition switch to ON.
Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection
Condition
Specified Condition
B75-20 (#10) - B75-51 (E01)
Ignition switch ON
11 to 14 V
B75-17 (#20) - B75-51 (E01)
Ignition switch ON
11 to 14 V
B75-18 (#30) - B75-51 (E01)
Ignition switch ON
11 to 14 V
B75-19 (#40) - B75-51 (E01)
Ignition switch ON
11 to 14 V
Result
Proceed to
OK
NG
-
CHECK FUEL INJECTOR ASSEMBLY OF MISFIRING CYLINDER
Check the fuel injector assembly injection (whether fuel volume is high or low, and whether injection pattern is poor) (Click here).
Tip:Perform "Inspection After Repairs" after replacing the fuel injector assembly (Click here).
Result
Proceed to
OK
NG
CHECK INTAKE SYSTEM
Check the intake system for vacuum leaks (Click here).
OK
No leaks from intake system.
Tip:Perform "Inspection After Repair" after repairing or replacing the intake system (Click here).
Result
Proceed to
OK
NG
NG REPAIR OR REPLACE INTAKE SYSTEM
CHECK FUEL PRESSURE
Check the fuel pressure (Click here).
Result
Proceed to
OK
NG
NG CHECK FUEL LINEClick here
READ VALUE USING GTS (COOLANT TEMP)
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Coolant Temp.
Powertrain > Engine and ECT > Data List
Tester Display
Coolant Temp
Read the Data List twice, when the engine is both cold and warmed up.
Standard
GTS Display
Condition
Specified Condition
Coolant Temp
Cold engine
Same as ambient air temperature
Warm engine
Between 75 and 100°C (167 and 212°F)
Tip:Perform "Inspection After Repair" after replacing the engine coolant temperature sensor (Click here).
Result
Proceed to
OK
NG
READ VALUE USING GTS (MAF)
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / MAF, Coolant Temp and Engine Speed.
Powertrain > Engine and ECT > Data List
Tester Display
Engine Speed
MAF
Coolant Temp
Allow the engine to idle until Coolant Temp reaches 75°C (167°F) or higher.
Read MAF with the engine speed at 3000 rpm.
Standard
GTS Display
Condition
Specified Condition
MAF
Shift lever position: N
A/C: Off
Engine Speed: 3000 rpm
Between 6.5 gm/s and 10.5 gm/s
Result
Proceed to
OK
NG
NG CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY CONNECTOR CONNECTION)Click here
ADJUST VALVE TIMING
Adjust the valve timing (Click hereClick here).
Tip:There are no marks on the cylinder head to match up for the purpose of checking valve timing. Valve timing can only be inspected by lining up the colored plates on the timing chain with the marks on the pulleys. It may be necessary to remove and reinstall the chain to match up the alignment marks.
Result
Proceed to
NEXT
CHECK WHETHER DTC OUTPUT RECURS (DTC P0300, P0301, P0302, P0303 OR P0304)
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Clear the DTCs (Click here).
Powertrain > Engine and ECT > Clear DTCs
Turn the ignition switch off and wait for at least 30 seconds.
Turn the ignition switch to ON.
Turn the GTS on.
Start the engine.
Warm up the engine.
Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
Powertrain > Engine and ECT > Utility
Tester Display
All Readiness
Input the DTC: P0300, P0301, P0302, P0303 or P0304.
Check the DTC judgment result.
Powertrain > Engine and ECT > Trouble Codes
Result
Result
Proceed to
ABNORMAL
(DTC P0300, P0301, P0302, P0303 or P0304 is output)
A
NORMAL
(DTC is not output)
B
A END
B CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY CONNECTOR CONNECTION)Click here
CHECK INTAKE SYSTEM
Check the intake system for vacuum leaks (Click here).
OK
No leaks from intake system.
Tip:Perform "Inspection After Repair" after repairing or replacing the intake system (Click here).
Result
Proceed to
OK
NG
NG REPAIR OR REPLACE INTAKE SYSTEM
CHECK FUEL PRESSURE
Check the fuel pressure (Click here).
Result
Proceed to
OK
NG
NG CHECK FUEL LINEClick here
READ VALUE USING GTS (COOLANT TEMP)
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Coolant Temp.
Powertrain > Engine and ECT > Data List
Tester Display
Coolant Temp
Read the Data List twice, when the engine is both cold and warmed up.
Standard
GTS Display
Condition
Specified Condition
Coolant Temp
Cold engine
Same as ambient air temperature
Warm engine
Between 75 and 100°C (167 and 212°F)
Tip:Perform "Inspection After Repair" after replacing the engine coolant temperature sensor (Click here).
Result
Proceed to
OK
NG
READ VALUE USING GTS (MAF)
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / MAF, Coolant Temp and Engine Speed.
Powertrain > Engine and ECT > Data List
Tester Display
Engine Speed
MAF
Coolant Temp
Allow the engine to idle until Coolant Temp reaches 75°C (167°F) or higher.
Read MAF with the engine speed at 3000 rpm.
Standard
GTS Display
Condition
Specified Condition
MAF
Shift lever position: N
A/C: Off
Engine Speed: 3000 rpm
Between 6.5 gm/s and 10.5 gm/s
Result
Proceed to
OK
NG
NG CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY CONNECTOR CONNECTION)Click here
INSPECT SPARK PLUG
Inspect the spark plug of the misfiring cylinder (Click here).
Tip:Perform "Inspection After Repair" after replacing the spark plug (Click here).
Result
Proceed to
OK
NG
CHECK FOR SPARKS (SPARK TEST)
Perform a spark test (Click here).
Tip:If the result of the spark test is normal, proceed to the next step.
Perform "Inspection After Repair" after repairing or replacing the ignition system (Click here).
Result
Proceed to
NEXT
CHECK CYLINDER COMPRESSION PRESSURE
Measure the cylinder compression pressure of the misfiring cylinder (Click here).
Tip:Perform "Inspection After Repair" after repairing or replacing the engine assembly (Click here).
Result
Proceed to
OK
NG
NG CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION
CHECK TERMINAL VOLTAGE (#10, #20, #30 AND/OR #40)
-
*a
Front view of wire harness connector
(to ECM)
Disconnect the ECM connector.
Turn the ignition switch to ON.
Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection
Condition
Specified Condition
B75-20 (#10) - B75-51 (E01)
Ignition switch ON
11 to 14 V
B75-17 (#20) - B75-51 (E01)
Ignition switch ON
11 to 14 V
B75-18 (#30) - B75-51 (E01)
Ignition switch ON
11 to 14 V
B75-19 (#40) - B75-51 (E01)
Ignition switch ON
11 to 14 V
Result
Proceed to
OK
NG
-
CHECK FUEL INJECTOR ASSEMBLY OF MISFIRING CYLINDER
Check the fuel injector assembly injection (whether fuel volume is high or low, and whether injection pattern is poor) (Click here).
Tip:Perform "Inspection After Repair" after replacing the fuel injector assembly (Click here).
Result
Proceed to
OK
NG
ADJUST VALVE TIMING
Adjust the valve timing (Click hereClick here).
Tip:There are no marks on the cylinder head to match up for the purpose of checking valve timing. Valve timing can only be inspected by lining up the colored plates on the timing chain with the marks on the pulleys. It may be necessary to remove and reinstall the chain to match up the alignment marks.
Result
Proceed to
NEXT
CHECK WHETHER DTC OUTPUT RECURS (DTC P0300, P0301, P0302, P0303 OR P0304)
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Clear the DTCs (Click here).
Powertrain > Engine and ECT > Clear DTCs
Turn the ignition switch off and wait for at least 30 seconds.
Turn the ignition switch to ON.
Turn the GTS on.
Start the engine.
Warm up the engine.
Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
Powertrain > Engine and ECT > Utility
Tester Display
All Readiness
Input the DTC: P0300, P0301, P0302, P0303 or P0304.
Check the DTC judgment result.
Result
Result
Proceed to
NORMAL
(DTC is not output)
A
ABNORMAL
(DTC P0300, P0301, P0302, P0303 or P0304 is output)
B
B END
CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY CONNECTOR CONNECTION)
Check the connection and terminal contact pressure of connectors and wire harnesses between the mass air flow meter sub-assembly and ECM (Click here).
Tip:Repair any problems.
Result
Proceed to
NEXT
CHECK WHETHER DTC OUTPUT RECURS (MISFIRE DTCS)
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Clear the DTCs (Click here).
Powertrain > Engine and ECT > Clear DTCs
Turn the ignition switch off and wait for at least 30 seconds.
Turn the ignition switch to ON.
Turn the GTS on.
Start the engine.
Warm up the engine.
Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
Powertrain > Engine and ECT > Utility
Tester Display
All Readiness
Input the DTC: P0300, P0301, P0302, P0303 or P0304.
Check the DTC judgment result.
Result
Result
Proceed to
ABNORMAL
(DTC P0300, P0301, P0302, P0303 or P0304 is output)
A
NORMAL
(DTC is not output)
B
B END
CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM)
Disconnect the mass air flow meter sub-assembly connector.
Disconnect the ECM connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection
Condition
Specified Condition
B1-5 (VG) - B75-91 (VG)
Always
Below 1 Ω
B1-4 (E2G) - B75-92 (E2G)
Always
Below 1 Ω
B1-5 (VG) or B75-91 (VG) - Body ground
Always
10 kΩ or higher
Result
Proceed to
OK
NG
NG REPAIR OR REPLACE HARNESS OR CONNECTOR
REPLACE MASS AIR FLOW METER SUB-ASSEMBLY
Replace the mass air flow meter sub-assembly (Click here).
Tip:If the results of the inspections performed in steps 13 and 19 indicated no problem, proceed to the next step without replacing the mass air flow meter sub-assembly.
Perform "Inspection After Repair" after replacing the mass air flow meter sub-assembly (Click here).
Result
Proceed to
NEXT
CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Clear the DTCs (Click here).
Powertrain > Engine and ECT > Clear DTCs
Turn the ignition switch off and wait for at least 30 seconds.
Turn the ignition switch to ON.
Turn the GTS on.
Start the engine.
Warm up the engine.
Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
Powertrain > Engine and ECT > Utility
Tester Display
All Readiness
Input the DTC: P0300, P0301, P0302, P0303 or P0304.
Check the DTC judgment result.
Result
Result
Proceed to
NORMAL
(DTC is not output)
A
ABNORMAL
(DTC P0300, P0301, P0302, P0303 or P0304 is output)
B
A END
CHECK FUEL LINE
Check the fuel lines for leaks or blockage.
Tip:Perform "Inspection After Repair" after replacing the fuel pump (Click here).
Result
Proceed to
OK
NG
NG REPAIR OR REPLACE FUEL LINE