Sfi System - P0304(2010/08 - )

1. Description

2. Confirmation driving pattern

3. Wiring diagram

4. Inspection procedure

5. Check any other dtcs output (in addition to misfire dtcs)

6. Check pcv hose connections

7. Read value using intelligent tester (misfire rpm and misfire load)

8. Read value using intelligent tester (cylinder #1, #2, #3 and #4 misfire count)

9. Inspect spark plug

10. Check for spark (spark test)

11. Check cylinder compression pressure of misfiring cylinder

12. Check fuel injector assembly (power source)

13. Check harness and connector (fuel injector assembly - ecm)

14. Inspect fuel injector assembly of misfiring cylinder

15. Check intake system

16. Check fuel pressure

17. Read value using intelligent tester (coolant temp)

18. Read value using intelligent tester (maf)

19. Check valve timing

20. Check valve clearance of misfiring cylinder

21. Check intake system

22. Check fuel pressure

23. Read value using intelligent tester (coolant temp)

24. Read value using intelligent tester (maf)

25. Check valve timing

26. Inspect spark plug

27. Check for spark (spark test)

28. Check cylinder compression pressure

29. Check fuel injector assembly (power source)

30. Check harness and connector (fuel injector assembly - ecm)

31. Inspect fuel injector assembly of misfiring cylinder

32. Check valve clearance of misfiring cylinder

33. Check harness and connector

34. Perform confirmation driving pattern

35. Check whether dtc output recurs (dtc p0300, p0301, p0302, p0303, p0304)

36. Check harness and connector (mass air flow meter sub-assembly - ecm)

37. Replace mass air flow meter

38. Perform confirmation driving pattern

39. Confirm whether malfunction has been successfully repaired

40. Change to normal spark plug and check spark of misfiring cylinder

41. Change to normal ignition coil assembly and check spark of misfiring cylinder

42. Check fuel line

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

CONFIRMATION DRIVING PATTERN

1. Connect the intelligent tester to the DLC3.
   
2. Turn the ignition switch to ON.
   
3. Turn the tester on.
   
4. Record the DTC(s) and freeze frame data.
   
5. Using the tester, switch the ECM from normal mode to check mode (Click here).
   
6. 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.
   
7. Drive the vehicle several times with the conditions, such as engine speed and engine load, shown in Misfire RPM and Misfire Load in the Data List.
   
   

   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.

   
   

   Engine Speed	Duration
   Idling	8 minutes or more
   1000	4.5 minutes or more
   2000	2.5 minutes or more
   3000	1.5 minutes or more

8. 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.

9. Record the DTC(s), freeze frame data and misfire counts.
   
10. Turn the ignition switch off and wait for at least 5 seconds.
    

WIRING DIAGRAM

INSPECTION PROCEDURE

HINT:

1. If any DTCs other than misfire DTCs are output, troubleshoot those DTCs first.
   
2. Read freeze frame data using the intelligent tester. 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.
   
3. 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.
   
4. 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:
   
5. 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.
      
6. After finishing repairs, check the misfire counts of the cylinders (Cylinder #1 Misfire Count to Cylinder #4 Misfire Count).
   
7. Be sure to confirm that no misfiring cylinder DTCs are stored again by conducting the confirmation driving pattern after finishing repairs.
   
8. 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).
   
9. When Coolant Temp in the freeze frame data is below 75°C (167°F), the misfires have occurred only while warming up the engine.
   
10. An extremely imbalanced drive wheel which causes body vibration may cause misfire DTCs detection.
    

1. Connect the intelligent tester to the DLC3.

2. Turn the ignition switch to ON.

3. Turn the tester on.

4. Enter the following menus: Powertrain / Engine and ECT / DTC.

5. 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

HINT:

If any DTCs other than P0300, P0301, P0302, P0303 and P0304 are output, troubleshoot those DTCs first.

B	GO TO DTC CHART (Click here)

A

1. Check the PCV hose connections.

   OK:

   PCV hose is correctly connected and is not damaged.
   

NG	REPAIR OR REPLACE PCV HOSE

OK

1. Connect the intelligent tester to the DLC3.

2. Turn the ignition switch to ON.

3. Turn the tester on.

4. Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Misfire RPM and Misfire Load.

5. 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

1. Connect the intelligent tester to the DLC3.

2. Turn the ignition switch to ON.

3. Turn the tester on.

4. Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Cylinder #1 (to #4) Misfire Count.

5. Read each value for Cylinder #1 (to #4) Misfire Count displayed on the tester. If no misfire counts occur in any cylinders, perform steps [A] and [B] and then check the misfire counts again.

6. Drive the vehicle with the Misfire RPM and Misfire Load noted in the "READ VALUE USING INTELLIGENT TESTER (MISFIRE RPM AND MISFIRE LOAD)" procedures above [A].

7. Read the Cylinder #1 (to #4) Misfire Count or DTCs displayed on the tester [B].
   

   Result:

   
   

   Result (Misfire Count)	Proceed to
   Most misfires occur in only 1 or 2 cylinders	A
   3 cylinders or more have equal misfire counts	B

HINT:

1. 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.
   
2. 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.
   
3. 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	Go to step 17

A

1. Inspect the spark plug of the misfiring cylinder (Click here).

NG	REPLACE SPARK PLUG (Click here)

OK

1. Perform a spark test (Click here).

   CAUTION:

   Always disconnect all injector connectors.

   NOTICE:

   Do not crank the engine for more than 2 seconds.

   OK:

   Spark jumps across electrode gap.
   

NG	Go to step 36

OK

1. Measure the cylinder compression pressure of the misfiring cylinder (Click here).

NG	CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

OK

1. Disconnect the fuel injector assembly connectors.

2. Turn the ignition switch to ON.

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

   Standard Voltage:

   Tester Connection	Condition	Specified Condition
   C7-1 - Body ground	Ignition switch ON	11 to 14 V
   C8-1 - Body ground	Ignition switch ON	11 to 14 V
   C9-1 - Body ground	Ignition switch ON	11 to 14 V
   C10-1 - Body ground	Ignition switch ON	11 to 14 V

   Text in Illustration

   *1	Front view of wire harness connector (to Fuel Injector Assembly)

4. Turn the ignition switch off.

5. Reconnect the fuel injector assembly connectors.

NG	CHECK FUEL INJECTOR CIRCUIT (Click here)

OK

1. Disconnect the fuel injector assembly connectors.

2. Disconnect the ECM connector.

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

   Standard Resistance (Check for Open):

   
   

   Tester Connection	Condition	Specified Condition
   C7-2 - C24-108 (#10)	Always	Below 1 Ω
   C9-2 - C24-107 (#20)	Always	Below 1 Ω
   C8-2 - C24-106 (#30)	Always	Below 1 Ω
   C10-2 - C24-105 (#40)	Always	Below 1 Ω

   
   

   Standard Resistance (Check for Short):

   
   

   Tester Connection	Condition	Specified Condition
   C7-2 or C24-108 (#10) - Body ground	Always	10 kΩ or higher
   C9-2 or C24-107 (#20) - Body ground	Always	10 kΩ or higher
   C8-2 or C24-106 (#30) - Body ground	Always	10 kΩ or higher
   C10-2 or C24-105 (#40) - Body ground	Always	10 kΩ or higher

4. Reconnect the fuel injector assembly connectors.

5. Reconnect the ECM connector.

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

OK

1. Inspect the fuel injector assembly injection (whether fuel volume is high or low, and whether injection pattern is poor) (Click here).

NG	REPLACE FUEL INJECTOR ASSEMBLY (Click here)

OK

1. Check the intake system for vacuum leaks.

   OK:

   No leaks in the intake system.
   

NG	REPAIR OR REPLACE INTAKE SYSTEM

OK

1. Check the fuel pressure (Click here).

NG	Go to step 38

OK

1. Connect the intelligent tester to the DLC3.

2. Turn the ignition switch to ON.

3. Turn the tester on.

4. Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Coolant Temp.

5. Read the Coolant Temp twice, when the engine is both cold and warmed up.

   Standard value:

   With cold engine:
   Same as ambient air temperature.
   With warm engine:
   Between 75°C and 100°C (176°F and 212°F).
   

NG	REPLACE ENGINE COOLANT TEMPERATURE SENSOR (Click here)

OK

1. Connect the intelligent tester to the DLC3.

2. Turn the ignition switch to ON.

3. Turn the tester on.

4. Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / MAF and Coolant Temp.

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

6. Read the MAF with the engine in an idling condition and at an engine speed of 2500 rpm.

   Standard:

   Between 6 g/sec. and 10 g/sec. (shift position: N, A/C: OFF).
   

NG	Go to step 29

OK

1. Remove the cylinder head cover.

2. Turn the crankshaft pulley, then align its groove with the timing mark "0" on the timing chain cover.

3. Check that the point marks on the camshaft timing gears are aligned with the timing chain cover surface as shown in the illustration.
   If not, turn the crankshaft 1 revolution (360°), then align the marks as above.

   OK:

   Alignment marks on camshaft timing gears are aligned as shown in the illustration.
   

   Text in Illustration

   *1	Alignment Marks
   *2	Groove

4. Reinstall the cylinder head cover.

NG	ADJUST VALVE TIMING (Click here)

OK

1. Check the valve clearance (Click here).

OK	Go to step 29
NG	ADJUST VALVE CLEARANCE (Click here)

1. Check the intake system for vacuum leaks.

   OK:

   No leaks in the intake system.
   

NG	REPAIR OR REPLACE INTAKE SYSTEM

OK

1. Check the fuel pressure (Click here).

NG	Go to step 38

OK

1. Check the fuel pressure (Click here).

   Standard pressure:

   304 to 343 kPa (3.1 to 3.5 kgf/cm², 44.1 to 49.7 psi)
   

NG	REPLACE ENGINE COOLANT TEMPERATURE SENSOR (Click here)

OK

1. Connect the intelligent tester to the DLC3.

2. Turn the ignition switch to ON.

3. Turn the tester on.

4. Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / MAF and Coolant Temp.

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

6. Read the MAF with the engine in an idling condition and at an engine speed of 2500 rpm.

   Standard:

   Between 6 g/sec. and 10 g/sec. (shift position: N, A/C: OFF).
   

NG	Go to step 29

OK

1. Remove the cylinder head cover.

2. Turn the crankshaft pulley, then align its groove with the timing mark "0" on the timing chain cover.

3. Check that the point marks on the camshaft timing gears are aligned with the timing chain cover surface as shown in the illustration.
   If not, turn the crankshaft 1 revolution (360°), then align the marks as above.

   OK:

   Alignment marks on camshaft timing gears are aligned as shown in the illustration.
   

   Text in Illustration

   *1	Alignment Marks
   *2	Groove

4. Reinstall the cylinder head cover.

NG	ADJUST VALVE TIMING (Click here)

OK

1. Inspect the spark plug of the misfiring cylinder (Click here).

NG	REPLACE SPARK PLUG (Click here)

OK

1. Perform a spark test (Click here).

   CAUTION:

   Always disconnect all injector connectors.

   NOTICE:

   Do not crank the engine for more than 2 seconds.

   OK:

   Spark jumps across electrode gap.
   

NG	Go to step 36

OK

1. Measure the cylinder compression pressure of the misfiring cylinder (Click here).

NG	CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

OK

1. Disconnect the fuel injector assembly connectors.

2. Turn the ignition switch to ON.

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

   Standard Voltage:

   Tester Connection	Condition	Specified Condition
   C7-1 - Body ground	Ignition switch ON	11 to 14 V
   C8-1 - Body ground	Ignition switch ON	11 to 14 V
   C9-1 - Body ground	Ignition switch ON	11 to 14 V
   C10-1 - Body ground	Ignition switch ON	11 to 14 V

   Text in Illustration

   *1	Front view of wire harness connector (to Fuel Injector Assembly)

4. Turn the ignition switch off.

5. Reconnect the fuel injector assembly connectors.

NG	CHECK FUEL INJECTOR CIRCUIT (Click here)

OK

1. Disconnect the fuel injector assembly connectors.

2. Disconnect the ECM connector.

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

   Standard Resistance (Check for Open):

   
   

   Tester Connection	Condition	Specified Condition
   C7-2 - C24-108 (#10)	Always	Below 1 Ω
   C9-2 - C24-107 (#20)	Always	Below 1 Ω
   C8-2 - C24-106 (#30)	Always	Below 1 Ω
   C10-2 - C24-105 (#40)	Always	Below 1 Ω

   
   

   Standard Resistance (Check for Short):

   
   

   Tester Connection	Condition	Specified Condition
   C7-2 or C24-108 (#10) - Body ground	Always	10 kΩ or higher
   C9-2 or C24-107 (#20) - Body ground	Always	10 kΩ or higher
   C8-2 or C24-106 (#30) - Body ground	Always	10 kΩ or higher
   C10-2 or C24-105 (#40) - Body ground	Always	10 kΩ or higher

4. Reconnect the fuel injector assembly connectors.

5. Reconnect the ECM connector.

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

OK

1. Inspect the fuel injector assembly injection (whether fuel volume is high or low, and whether injection pattern is poor) (Click here).

NG	REPLACE FUEL INJECTOR ASSEMBLY (Click here)

OK

1. Check the valve clearance (Click here).

NG	ADJUST VALVE CLEARANCE (Click here)

OK

1. Check the connection and terminal contact pressure of connectors and wire harness between the mass air flow meter and ECM (Click here).

   HINT:

   Repair any problems.

NEXT

1. Connect the intelligent tester to the DLC3.

2. Turn the ignition switch to ON.

3. Turn the tester on.

4. Clear the DTCs (Click here).

5. Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.

NEXT

1. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

2. Input the DTC: P0300, P0301, P0302, P0303 or P0304.

3. 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

A

1. Disconnect the mass air flow meter sub-assembly connector.

2. Disconnect the ECM connector.

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

   Standard Resistance (Check for Open):

   
   

   Tester Connection	Condition	Specified Condition
   C2-5 (VG) - C24-118 (VG)	Always	Below 1 Ω
   C2-4 (E2G) - C24-116 (E2G)	Always	Below 1 Ω

   
   

   Standard Resistance (Check for Short):

   
   

   Tester Connection	Condition	Specified Condition
   C2-5 (VG) or C24-118 (VG) - Body ground	Always	10 kΩ or higher

4. Reconnect the ECM connector.

5. Reconnect the mass air flow meter sub-assembly connector.

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM)

OK

1. Replace the mass air flow meter (Click here).

HINT:

If the result of the inspection performed in steps 14 and 20 indicated no problem, proceed to the next step without replacing the mass air flow meter.

NEXT

1. Connect the intelligent tester to the DLC3.

2. Turn the ignition switch to ON.

3. Turn the tester on.

4. Clear the DTCs (Click here).

5. Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.

NEXT

1. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

2. Input the DTC: P0300, P0301, P0302, P0303 or P0304.

3. 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	REPLACE ECM (Click here)

A
END

1. Change the installed spark plug to a known good spark plug.

2. Perform a spark test (Click here).

   CAUTION:

   Always disconnect all injector connectors.

   NOTICE:

   Do not crank the engine for more than 2 seconds.

   OK:

   Spark jumps across electrode gap.
   

NG	Go to step 37

OK
REPLACE SPARK PLUG (Click here)

1. Change the installed ignition coil assembly to a known good ignition coil assembly.

2. Perform a spark test (Click here).

   CAUTION:

   Always disconnect all injector connectors.

   NOTICE:

   Do not crank the engine for more than 2 seconds.

   OK:

   Spark jumps across electrode gap.
   

NG	REPLACE ECM (Click here)

OK
REPLACE IGNITION COIL ASSEMBLY (Click here)

1. Check the fuel lines for leaks or blockage.

NG	REPAIR OR REPLACE FUEL LINE

OK
REPLACE FUEL PUMP (Click here)