SFI SYSTEM, Diagnostic DTC:P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308

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
P0305	Cylinder 5 Misfire Detected
P0306	Cylinder 6 Misfire Detected
P0307	Cylinder 7 Misfire Detected
P0308	Cylinder 8 Misfire Detected

DESCRIPTION

When the engine misfires, high concentrations of hydrocarbons (HC) enter the exhaust gas. Extremely high HC concentration levels can cause increases in exhaust emission levels. High concentrations of HC can also cause increases in the Three-Way Catalytic Converter (TWC) temperature, which may cause damage to the TWC. To prevent these increases in emissions and to limit the possibility of thermal damage, the ECM monitors the misfire rate. When the temperature of the TWC reaches the point of thermal degradation, the MIL blinks. To monitor misfires, the ECM uses both the Camshaft Position (CMP) sensor and the Crankshaft Position (CKP) sensor. The CMP sensor is used to identify any misfiring cylinders and the CKP sensor is used to measure variations in the crankshaft rotation speed. Misfires are counted as when the crankshaft rotation speed variations exceed predetermined thresholds.

If the misfire rate exceeds the threshold level, the ECM illuminates the MIL and stores DTC(s).

DTC Code	DTC Detection Condition	Trouble Area
P0300	Simultaneous misfiring of several cylinders occurs and one of the following conditions below is detected (2 trip detection logic): A high temperature misfire occurs in the Three-Way Catalytic Converter (TWC) (MIL blinks when detect immediately). An emission deterioration misfire occurs (MIL illuminates).	Open or short in engine wire harness Connector connection Vacuum hose connections Ignition system Fuel injector Fuel pressure Mass Air Flow (MAF) meter Engine Coolant Temperature (ECT) sensor Compression pressure Valve timing PCV valve and hose PCV hose connections Air induction system ECM
P0301 P0302 P0303 P0304 P0305 P0306 P0307 P0308	Misfiring of a specific cylinder occurs and one of the following conditions below is detected (2 trip detection logic): A high temperature misfire occurs in the Three-Way Catalytic Converter (TWC) (MIL blinks when detect immediately). An emission deterioration misfire occurs (MIL illuminates).

DTC Code

DTC Detection Condition

Trouble Area

P0300

Simultaneous misfiring of several cylinders occurs and one of the following conditions below is detected (2 trip detection logic):

A high temperature misfire occurs in the Three-Way Catalytic Converter (TWC) (MIL blinks when detect immediately).
An emission deterioration misfire occurs (MIL illuminates).

Open or short in engine wire harness
Connector connection
Vacuum hose connections
Ignition system
Fuel injector
Fuel pressure
Mass Air Flow (MAF) meter
Engine Coolant Temperature (ECT) sensor
Compression pressure
Valve timing
PCV valve and hose
PCV hose connections
Air induction system
ECM

P0301

P0302

P0303

P0304

P0305

P0306

P0307

P0308

Misfiring of a specific cylinder occurs and one of the following conditions below is detected (2 trip detection logic):

A high temperature misfire occurs in the Three-Way Catalytic Converter (TWC) (MIL blinks when detect immediately).
An emission deterioration misfire occurs (MIL illuminates).

Tech Tips

When multiple 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 30 to 110 misfires per 1000 crankshaft revolutions) occurs once.
An excessive misfiring rate (approximately 30 to 110 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 the Three-Way Catalytic Converter (TWC) damage, is detected.

At a high engine speed, a catalyst damage misfire, which monitored every 200 crankshaft revolutions, occurs once.
At a normal engine speed, a catalyst damage misfire, which monitored every 200 crankshaft revolutions, occurs 3 times.

Tech Tips

If a catalyst damage misfire occurs, the ECM informs the driver by flashing the MIL.

WIRING DIAGRAM

CONFIRMATION DRIVING PATTERN

Connect the intelligent tester to the DLC3.
Turn the engine switch on (IG).
Turn the tester on.
Record the DTC(s) and freeze frame data.
Using the tester, switch the ECM from normal mode to check mode Click here.
Read the misfire counts of each cylinder (cylinder No. 1 to No. 8) with the engine in an idling condition. If any misfire count is displayed, skip the following confirmation driving pattern.

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.

Tech Tips

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 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

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

Tech Tips

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

INSPECTION PROCEDURE

Tech Tips

DTC P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 and P0308 are for Euro-OBD only.
If any DTCs other than misfire DTCs are output, troubleshoot those DTCs first.
Read freeze frame data using the intelligent tester. Freeze frame data records the engine condition when malfunctions are detected. 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 freeze frame data.
If the misfire still cannot be reproduced even though the conditions stored in the freeze frame data have been duplicated, one of the following factors is considered to be a possible cause of the problem:

The fuel level is low.
Improper fuel is used.
The spark plugs are dirty.

After finishing repairs, check that no misfires occur in each cylinder (cylinder No. 1, No. 2, No. 3, No. 4, No. 5, No. 6, No. 7 and No. 8).
Be sure to confirm that no misfiring cylinder DTCs are output again by conducting the confirmation driving pattern after the repairs.
For 6 and 8 cylinder engines, the ECM intentionally does not store the specific misfiring cylinder DTCs at high engine speed. If misfires only occur during high engine speed driving, only DTC P0300 is stored.

In the event of DTC P0300 being present, perform the following operations:

Clear the DTC Click here.
Start the engine and conduct the confirmation driving pattern.
Read the misfiring rates of each cylinder or DTC(s) using the intelligent tester.
Repair the cylinder(s) that has a high misfiring rate or is indicated by the DTC.
After finishing repairs, conduct the confirmation driving pattern again, in order to verify that DTC P0300 is not output.

When either 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 below 75°C (167°F), the misfires occurred only while warming up the engine.
An extremely imbalanced drive wheel which causes body vibration may cause misfire DTCs to be detected.

PROCEDURE

CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO MISFIRE CODES)

Connect the intelligent tester to the DLC3.
Turn the engine switch on (IG).
Turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / DTC.

Read DTCs.

Result
Result	Proceed to
P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 and/or P0308 are output	A
P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 and/or P0308 and other DTCs are output	B

Tech Tips

If any DTCs other than P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 and P0308 are output, troubleshoot those DTCs first.

GO TO DTC CHART Click here

READ VALUE USING INTELLIGENT TESTER (MISFIRE RPM AND MISFIRE LOAD)
1. Connect the intelligent tester the DLC3.
2. Turn the engine switch on (IG) and turn the tester on.
3. Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Misfire RPM and Misfire Load.
4. Read and note the Misfire RPM and Misfire Load values.
  
  Tech Tips
  
  The Misfire RPM and Misfire Load values indicate the vehicle conditions under which the misfire occurred.
NEXT
CHECK PCV HOSE CONNECTIONS
1. Check the PCV hose connections.
  
  OK
  
  PCV hose is connected correctly and is not damaged.
NG
REPAIR OR REPLACE PCV HOSE Click here

OK

OK
PCV hose is connected correctly and is not damaged.

READ VALUE USING INTELLIGENT TESTER (MISFIRE COUNT)

Connect the intelligent tester to the DLC3.
Turn the engine switch on (IG).
Turn the tester on.
Clear DTCs Click here.
Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Cylinder #1 Misfire Count, #2, #3, #4, #5, #6, #7 and #8.
Allow the engine to idle.
Read each value for Cylinder #1 Misfire Count to #8 displayed on the tester. If no misfire counts occur in any cylinders, perform the following procedures:
1. Move the shift lever to D.
2. Check the Cylinder #1 Misfire Count to #8.
3. If misfire counts are still not displayed, 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 tester (Misfire RPM and Misfire Load)" procedures above (Procedure "A").

Read the Cylinder #1 Misfire Count to #8 or DTCs displayed on the tester (Procedure "B").

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

Tech Tips

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 ECT 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.

CHECK AIR INDUCTION SYSTEM Click here

CHECK SPARK PLUG

Remove the ignition coil and the spark plug of the misfiring cylinder Click here.
Measure the spark plug electrode gap.

Standard gap

1.0 to 1.1 mm (0.0394 to 0.0433 in.)

Standard gap
1.0 to 1.1 mm (0.0394 to 0.0433 in.)

Check the electrode for carbon deposits.

Recommended Spark Plug:
Manufacturer	Product
DENSO	SK20HR11

Note

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

REPLACE SPARK PLUG Click here

CHECK FOR SPARKS AND IGNITION
1. Disconnect the injector connectors to prevent the engine from starting.
  
  CAUTION:
  
  Always disconnect all injector connectors.
  
  Note
  
  Do not crank the engine for more than 2 seconds.
2. Remove the ignition coil from the cylinder head Click here.
3. Install the spark plug onto the ignition coil.
4. Attach the spark plug assembly to the cylinder head.
5. Crank the engine for less than 2 seconds and check the spark.
  
  OK
  
  Sparks jump across electrode gap.
6. Install the ignition coil.
7. Reconnect the injector connectors.
NG
CHANGE TO SPARK PLUG Click here

OK
CHECK CYLINDER COMPRESSION PRESSURE
1. Measure the cylinder compression pressure of the misfiring cylinder Click here.
NG
REPAIR ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

OK

OK
Sparks jump across electrode gap.

INSPECT ECM TERMINAL OF MISFIRING CYLINDER (#10, #20, #30, #40, #50, #60, #70 AND/OR #80 VOLTAGE)

Disconnect the ECM connector.

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

Standard Voltage

for LHD
Tester Connection	Switch Condition	Specified Condition
C53-86 (#10) - C53-43 (E01)	Engine switch on (IG)	11 to 14 V
C53-109 (#20) - C53-43 (E01)	Engine switch on (IG)	11 to 14 V
C53-85 (#30) - C53-43 (E01)	Engine switch on (IG)	11 to 14 V
C53-108 (#40) - C53-43 (E01)	Engine switch on (IG)	11 to 14 V
C53-84 (#50) - C53-43 (E01)	Engine switch on (IG)	11 to 14 V
C53-107 (#60) - C53-43 (E01)	Engine switch on (IG)	11 to 14 V
C53-83 (#70) - C53-43 (E01)	Engine switch on (IG)	11 to 14 V
C53-106 (#80) - C53-43 (E01)	Engine switch on (IG)	11 to 14 V

for RHD
Tester Connection	Switch Condition	Specified Condition
C54-86 (#10) - C54-43 (E01)	Engine switch on (IG)	11 to 14 V
C54-109 (#20) - C54-43 (E01)	Engine switch on (IG)	11 to 14 V
C54-85 (#30) - C54-43 (E01)	Engine switch on (IG)	11 to 14 V
C54-108 (#40) - C54-43 (E01)	Engine switch on (IG)	11 to 14 V
C54-84 (#50) - C54-43 (E01)	Engine switch on (IG)	11 to 14 V
C54-107 (#60) - C54-43 (E01)	Engine switch on (IG)	11 to 14 V
C54-83 (#70) - C54-43 (E01)	Engine switch on (IG)	11 to 14 V
C54-106 (#80) - C54-43 (E01)	Engine switch on (IG)	11 to 14 V

GO TO FUEL INJECTOR CIRCUIT Click here

CHECK FUEL INJECTOR OF MISFIRING CYLINDER
1. Check the injector injection [whether fuel volume is high or low, and whether injection pattern is poor] Click here.
NG
REPLACE FUEL INJECTOR ASSEMBLY Click here

OK
CHECK AIR INDUCTION SYSTEM
1. Check the air induction system for vacuum leakage Click here.
  
  OK
  
  No leakage from air induction system.
NG
REPAIR OR REPLACE AIR INDUCTION SYSTEM Click here

OK
CHECK VALVE TIMING
1. Remove the cylinder head cover LH and RH.
2. Turn the crankshaft pulley, and align its groove with the timing mark "0" of the timing chain cover.
3. Check that the timing marks of the camshaft timing gears and camshaft timing exhaust gears are at the positions shown in the illustration.
  
  OK
  
  Timing marks on camshaft timing gears are aligned as shown in the illustration.
NG
ADJUST VALVE TIMING Click here

OK
CHECK FUEL PRESSURE
1. Check the fuel pressure Click here.
NG
CHECK AND REPLACE FUEL PUMP, PRESSURE REGULATOR, FUEL PIPE LINE AND FILTER

OK

OK
No leakage from air induction system.

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

READ VALUE USING INTELLIGENT TESTER (COOLANT TEMP)

Connect the intelligent tester to the DLC3.
Turn the engine switch on (IG) and turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Coolant Temp.

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

Standard
With cold engine: Same as ambient air temperature.
With warm engine: Between 75°C and 100°C (167°F and 212°F).

REPLACE ENGINE COOLANT TEMPERATURE SENSOR Click here

INSPECT MASS AIR FLOW METER
1. Inspect the mass air flow meter Click here.
NG
REPLACE MASS AIR FLOW METER Click here

OK

REPLACE ECM Click here
CHECK AIR INDUCTION SYSTEM
1. Check the air induction system for vacuum leakage Click here.
  
  OK
  
  No leakage from air induction system.
NG
REPAIR OR REPLACE AIR INDUCTION SYSTEM Click here

OK
CHECK VALVE TIMING
1. Remove the cylinder head cover LH and RH.
2. Turn the crankshaft pulley, and align its groove with the timing mark "0" of the timing chain cover.
3. Check that the timing marks of the camshaft timing gears and camshaft timing exhaust gears are at the positions shown in the illustration.
  
  OK
  
  Timing marks on camshaft timing gears are aligned as shown in the illustration.
NG
ADJUST VALVE TIMING Click here

OK
CHECK FUEL PRESSURE
1. Check the fuel pressure Click here.
NG
CHECK AND REPLACE FUEL PUMP, PRESSURE REGULATOR, FUEL PIPE LINE AND FILTER

OK

OK
No leakage from air induction system.

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

READ VALUE USING INTELLIGENT TESTER (COOLANT TEMP)

Connect the intelligent tester to the DLC3.
Turn the engine switch on (IG) and turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Coolant Temp.

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

Standard
With cold engine: Same as ambient air temperature.
With warm engine: Between 75°C and 100°C (167°F and 212°F).

REPLACE ENGINE COOLANT TEMPERATURE SENSOR Click here

INSPECT MASS AIR FLOW METER
1. Inspect the mass air flow meter Click here.
NG
REPLACE MASS AIR FLOW METER Click here

OK

CHECK SPARK PLUG

Remove the ignition coil and the spark plug of the misfiring cylinder Click here.
Measure the spark plug electrode gap.

Standard gap

1.0 to 1.1 mm (0.0394 to 0.0433 in.)

Check the electrode for carbon deposits.

Recommended Spark Plug:
Manufacturer	Product
DENSO	SK20HR11

Note

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

REPLACE SPARK PLUG Click here

CHECK FOR SPARKS AND IGNITION
1. Disconnect the injector connectors to prevent the engine from starting.
  
  CAUTION:
  
  Always disconnect all injector connectors.
  
  Note
  
  Do not crank the engine for more than 2 seconds.
2. Remove the ignition coil from the cylinder head Click here.
3. Install the spark plug onto the ignition coil.
4. Attach the spark plug assembly to the cylinder head.
5. Crank the engine for less than 2 seconds and check the spark.
  
  OK
  
  Sparks jump across electrode gap.
6. Install the ignition coil.
7. Reconnect the injector connectors.
NG
CHANGE TO SPARK PLUG Click here

OK
CHECK CYLINDER COMPRESSION PRESSURE
1. Measure the cylinder compression pressure of the misfiring cylinder Click here.
NG
REPAIR ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

OK

INSPECT ECM TERMINAL OF MISFIRING CYLINDER (#10, #20, #30, #40, #50, #60, #70 AND/OR #80 VOLTAGE)

Disconnect the ECM connector.

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

Standard Voltage

for LHD
Tester Connection	Switch Condition	Specified Condition
C53-86 (#10) - C53-43 (E01)	Engine switch on (IG)	11 to 14 V
C53-109 (#20) - C53-43 (E01)	Engine switch on (IG)	11 to 14 V
C53-85 (#30) - C53-43 (E01)	Engine switch on (IG)	11 to 14 V
C53-108 (#40) - C53-43 (E01)	Engine switch on (IG)	11 to 14 V
C53-84 (#50) - C53-43 (E01)	Engine switch on (IG)	11 to 14 V
C53-107 (#60) - C53-43 (E01)	Engine switch on (IG)	11 to 14 V
C53-83 (#70) - C53-43 (E01)	Engine switch on (IG)	11 to 14 V
C53-106 (#80) - C53-43 (E01)	Engine switch on (IG)	11 to 14 V

for RHD
Tester Connection	Switch Condition	Specified Condition
C54-86 (#10) - C54-43 (E01)	Engine switch on (IG)	11 to 14 V
C54-109 (#20) - C54-43 (E01)	Engine switch on (IG)	11 to 14 V
C54-85 (#30) - C54-43 (E01)	Engine switch on (IG)	11 to 14 V
C54-108 (#40) - C54-43 (E01)	Engine switch on (IG)	11 to 14 V
C54-84 (#50) - C54-43 (E01)	Engine switch on (IG)	11 to 14 V
C54-107 (#60) - C54-43 (E01)	Engine switch on (IG)	11 to 14 V
C54-83 (#70) - C54-43 (E01)	Engine switch on (IG)	11 to 14 V
C54-106 (#80) - C54-43 (E01)	Engine switch on (IG)	11 to 14 V

GO TO FUEL INJECTOR CIRCUIT Click here

CHECK FUEL INJECTOR OF MISFIRING CYLINDER
1. Check the injector injection [whether fuel volume is high or low, and whether injection pattern is poor] Click here.
NG
REPLACE FUEL INJECTOR ASSEMBLY Click here

OK

REPLACE ECM Click here
CHANGE TO SPARK PLUG
1. Change the installed spark plug to a spark plug that functions normally.
2. Perform a spark test.
  
  CAUTION:
  
  Always disconnect all injector connectors.
  
  Note
  
  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 AND CHECK SPARK OF MISFIRING CYLINDER Click here

OK

REPLACE SPARK PLUG Click here
CHANGE TO NORMAL IGNITION COIL AND CHECK SPARK OF MISFIRING CYLINDER
1. Change the ignition coil to an ignition coil that functions normally.
2. Perform a spark test.
  
  CAUTION:
  
  Always disconnect all injector connectors.
  
  Note
  
  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
REPLACE ECM Click here

OK

REPLACE IGNITION COIL Click here