When the engine misfires, high concentrations of hydrocarbons (HC) enter the exhaust gas. Extremely high HC concentration levels can cause increases in exhaust emissions levels. High concentrations of HC can also cause increases in the Three-way Catalytic Converter (TWC) temperature, which may cause damage to the Three-way Catalytic Converter (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 Three-way Catalytic Converter (TWC) reaches the point of thermal degradation, the MIL blinks. To monitor misfires, the ECM uses both the VVT sensor and the crankshaft position sensor. The VVT sensor is used to identify any misfiring cylinders and the crankshaft position sensor is used to measure variations in the crankshaft rotation speed. A misfire is counted when the crankshaft rotation speed variations exceed predetermined thresholds.

If the misfire rate exceeds the threshold, the ECM illuminates the MIL and stores a DTC.

DTC No.	DTC Detection Condition	Trouble Area
P0300	Simultaneous misfiring of several cylinders occurs and one of the following conditions is met (2 trip detection logic): A misfire occurs that may damage the three-way catalytic converter (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 assembly Fuel pressure Mass air flow meter Engine coolant temperature sensor Compression pressure Valve timing PCV valve and hose PCV hose connections Intake system ECM
P0301 P0302 P0303 P0304 P0305 P0306	Misfiring of a specific cylinder occurs and one of the following conditions is met (2 trip detection logic): A misfire occurs that may damage the three-way catalytic converter (MIL blinks when detect immediately). An emission deterioration misfire occurs (MIL illuminates).

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 the following condition, which could cause emission deterioration, is detected (2 trip detection logic).

An excessive number of misfires (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 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.

WIRING DIAGRAM

Refer to DTC P0102 ().

Refer to DTC P0351 ().

Refer to Fuel Injector Circuit ().

CONFIRMATION DRIVING PATTERN

Connect the GTS to the DLC3.

Turn the ignition switch to ON.

Turn the GTS on.

Record the DTCs and freeze frame data.

Clear the DTCs (even if no DTCs are stored, perform the clear DTC operation).

Using the GTS, switch the ECM from normal mode to check mode ().

Read the misfire counts of each cylinder (cylinder No. 1 to No. 6) with the engine idling. 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, as 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.

Engine Speed	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.

HINT:

Do not turn the ignition switch off until the stored DTCs and freeze frame data have been recorded. When the ECM returns to normal mode (default), the stored DTCs, freeze frame data and other data will be cleared.

Record the DTCs, 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 operation).

INSPECTION PROCEDURE

HINT:

If any DTCs other than misfire DTCs are output, troubleshoot those DTCs first.

Read freeze frame data using the GTS. 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 misfire does not recur when the vehicle is brought to the workshop, reproduce the conditions stored in the ECM as freeze frame data.

If 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 may be a cause of the problem:

The fuel level is low.

Improper fuel is being 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 and No. 6).

Be sure to confirm that no misfiring cylinder DTCs are stored 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 speeds. If misfires only occur during high engine speed driving, only DTC P0300 is stored.
In the event of DTC P0300 being output, perform the following operations:

Clear the DTCs ().

Start the engine and conduct the confirmation driving pattern.

Read the misfire counts of each cylinder or the DTCs using the GTS.

Repair the cylinders that have a high misfire count or are indicated by DTCs.

After finishing repairs, conduct the confirmation driving pattern again in order to verify that DTC P0300 is not stored.

When 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 Coolant Temp in the freeze frame data is below 75°C (167°F), the misfires may have occurred while warming up the engine.

An extremely imbalanced drive wheel which causes body vibration may cause misfire DTCs to be stored.

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

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.

Read the DTCs.

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

HINT:

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

GO TO DTC CHART ()

A

2.CHECK PCV HOSE CONNECTIONS

Check the PCV hose (w/ secondary air injection system) connections ().

Check the PCV hose (w/o secondary air injection system) connections ().

OK:
PCV hose is connected correctly and is not damaged.

REPAIR OR REPLACE PCV HOSE ()

OK

3.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.

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

4.READ VALUE USING GTS

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 / Catalyst OT MF F/C.

Read the value displayed on the GTS.

Result
Data List	GTS Display	Proceed to
Catalyst OT MF F/C	AVAIL (Avail)	A
Catalyst OT MF F/C	NOT AVL (Not Avl)	B

Go to step 6

A

5.PERFORM ACTIVE TEST USING GTS

Connect the GTS to the DLC3.

Turn the ignition switch to ON.

Turn the GTS on.

Clear the DTCs ().

Enter the following menus: Powertrain / Engine and ECT / Active Test / Prohibit the Catalyst OT Misfire prevent F/C.

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

6.READ VALUE USING GTS (MISFIRE COUNT)

Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Cylinder #1 Misfire Count, #2, #3, #4, #5 and #6.

Allow the engine to idle.

Read the values for Cylinder #1 Misfire Count to Cylinder #6 Misfire Count displayed on the GTS. If no misfires are counted in any cylinders, perform the following procedure:

Move the shift lever to D.

Check Cylinder #1 Misfire Count to Cylinder #6 Misfire Count.

If misfires are still not being counted, perform procedures "A" and "B", and then check the misfire counts again.

Procedure A: Drive the vehicle while matching the vehicle conditions to the Misfire RPM and Misfire Load values noted in the "Read Value Using GTS (Misfire RPM and Misfire Load)" procedure above.

Procedure B: Read Cylinder #1 Misfire Count to Cylinder #6 Misfire Count or the DTCs output on the GTS.

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

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 engine coolant temperature is below 75°C (167°F), misfire may be detected only when the engine is cold.

If the freeze frame data's record of the Engine Run Time is less than 120 seconds, misfire may only be detected immediately after the engine is started.

Go to step 18

A

7.INSPECT SPARK PLUG

Inspect the spark plug of the misfiring cylinder ().

REPLACE SPARK PLUG ()

OK

8.CHECK FOR SPARKS AND IGNITION

Perform a spark test ().

HINT:

If the result of the spark test is normal, proceed to the next step.

NEXT

9.CHECK CYLINDER COMPRESSION PRESSURE

Measure the cylinder compression pressure of the misfiring cylinder ().

CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

OK

10.CHECK FUEL INJECTOR ASSEMBLY (POWER SOURCE)

Disconnect the fuel injector assembly connector.

Turn the ignition switch to ON.

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

Standard Voltage:

Cylinder	Tester Connection	Switch Condition	Specified Condition
No. 1	C5-1 - Body ground	Ignition switch ON	11 to 14 V
No. 2	C16-1 - Body ground	Ignition switch ON	11 to 14 V
No. 3	C7-1 - Body ground	Ignition switch ON	11 to 14 V
No. 4	C14-1 - Body ground	Ignition switch ON	11 to 14 V
No. 5	C9-1 - Body ground	Ignition switch ON	11 to 14 V
No. 6	C12-1 - Body ground	Ignition switch ON	11 to 14 V

Text in Illustration
*a	Front view of wire harness connector (to Fuel Injector Assembly)

Turn the ignition switch off.

GO TO FUEL INJECTOR CIRCUIT ()

OK

11.CHECK HARNESS AND CONNECTOR

Disconnect the fuel injector assembly connector.

Disconnect the ECM connector.

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

Standard Resistance:

for LHD
Cylinder	Tester Connection	Condition	Specified Condition
No. 1	C5-2 - Body ground	Always	10 kΩ or higher
No. 1	C5-2 - C45-86 (#10)	Always	Below 1 Ω
No. 2	C16-2 - Body ground	Always	10 kΩ or higher
No. 2	C16-2 - C45-109 (#20)	Always	Below 1 Ω
No. 3	C7-2 - Body ground	Always	10 kΩ or higher
No. 3	C7-2 - C45-85 (#30)	Always	Below 1 Ω
No. 4	C14-2 - Body ground	Always	10 kΩ or higher
No. 4	C14-2 - C45-108 (#40)	Always	Below 1 Ω
No. 5	C9-2 - Body ground	Always	10 kΩ or higher
No. 5	C9-2 - C45-84 (#50)	Always	Below 1 Ω
No. 6	C12-2 - Body ground	Always	10 kΩ or higher
No. 6	C12-2 - C45-107 (#60)	Always	Below 1 Ω

for RHD
Cylinder	Tester Connection	Condition	Specified Condition
No. 1	C5-2 - Body ground	Always	10 kΩ or higher
No. 1	C5-2 - C46-86 (#10)	Always	Below 1 Ω
No. 2	C16-2 - Body ground	Always	10 kΩ or higher
No. 2	C16-2 - C46-109 (#20)	Always	Below 1 Ω
No. 3	C7-2 - Body ground	Always	10 kΩ or higher
No. 3	C7-2 - C46-85 (#30)	Always	Below 1 Ω
No. 4	C14-2 - Body ground	Always	10 kΩ or higher
No. 4	C14-2 - C46-108 (#40)	Always	Below 1 Ω
No. 5	C9-2 - Body ground	Always	10 kΩ or higher
No. 5	C9-2 - C46-84 (#50)	Always	Below 1 Ω
No. 6	C12-2 - Body ground	Always	10 kΩ or higher
No. 6	C12-2 - C46-107 (#60)	Always	Below 1 Ω

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

12.CHECK FUEL INJECTOR ASSEMBLY OF MISFIRING CYLINDER

Check the fuel injector injection [whether fuel volume is high or low, and whether injection pattern is poor] ().

REPLACE FUEL INJECTOR ASSEMBLY ()

OK

13.CHECK INTAKE SYSTEM

Check the intake system for vacuum leakage ().

OK:
No leakage in intake system.

REPAIR OR REPLACE INTAKE SYSTEM

OK

14.CHECK FUEL PRESSURE

Check the fuel pressure ().

Go to step 34

OK

15.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.

Read 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 ()

OK

16.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 and 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:
Between 18.3 gm/s and 25.8 gm/s (shift lever: N; A/C: off).

Go to step 29

OK

17.CHECK VALVE TIMING

Remove the cylinder head cover RH and LH.

Text in Illustration
*1	Timing Mark

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

Check that the timing marks on the camshaft timing gears are aligned with the timing marks of the bearing cap as shown in the illustration.

If not, turn the crankshaft 1 revolution (360°), and then align the marks as above.

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

Reinstall the cylinder head cover RH and LH.

Go to step 29

CHECK ENGINE MECHANICAL SYSTEM ()

18.CHECK INTAKE SYSTEM

Check the intake system for vacuum leakage ().

OK:
No leakage in intake system.

REPAIR OR REPLACE INTAKE SYSTEM

OK

19.CHECK FUEL PRESSURE

Check the fuel pressure ().

Go to step 34

OK

20.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.

Read 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 ()

OK

21.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 and 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:
Between 18.3 gm/sec and 25.8 gm/sec (shift lever: N; A/C: off).

Go to step 29

OK

22.CHECK VALVE TIMING

Remove the cylinder head cover RH and LH.

Text in Illustration
*1	Timing Mark

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

Check that the timing marks on the camshaft timing gears are aligned with the timing marks of the bearing cap as shown in the illustration.

If not, turn the crankshaft 1 revolution (360°), and then align the marks as above.

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

Reinstall the cylinder head cover RH and LH.

CHECK ENGINE MECHANICAL SYSTEM ()

OK

23.INSPECT SPARK PLUG

Inspect the spark plug of the misfiring cylinder ().

REPLACE SPARK PLUG ()

OK

24.CHECK FOR SPARKS AND IGNITION

Perform a spark test ().

HINT:

If the result of the spark test is normal, proceed to the next step.

NEXT

25.CHECK CYLINDER COMPRESSION PRESSURE

Measure the cylinder compression pressure of the misfiring cylinder ().

CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

OK

26.CHECK FUEL INJECTOR ASSEMBLY (POWER SOURCE)

Disconnect the fuel injector assembly connector.

Turn the ignition switch to ON.

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

Standard Voltage:

Cylinder	Tester Connection	Switch Condition	Specified Condition
No. 1	C5-1 - Body ground	Ignition switch ON	11 to 14 V
No. 2	C16-1 - Body ground	Ignition switch ON	11 to 14 V
No. 3	C7-1 - Body ground	Ignition switch ON	11 to 14 V
No. 4	C14-1 - Body ground	Ignition switch ON	11 to 14 V
No. 5	C9-1 - Body ground	Ignition switch ON	11 to 14 V
No. 6	C12-1 - Body ground	Ignition switch ON	11 to 14 V

Text in Illustration
*a	Front view of wire harness connector (to Fuel Injector Assembly)

Turn the ignition switch off.

GO TO FUEL INJECTOR CIRCUIT ()

OK

27.CHECK HARNESS AND CONNECTOR (FUEL INJECTOR ASSEMBLY - ECM)

Disconnect the fuel injector assembly connector.

Disconnect the ECM connector.

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

Standard Resistance:

for LHD
Cylinder	Tester Connection	Condition	Specified Condition
No. 1	C5-2 - Body ground	Always	10 kΩ or higher
No. 1	C5-2 - C45-86 (#10)	Always	Below 1 Ω
No. 2	C16-2 - Body ground	Always	10 kΩ or higher
No. 2	C16-2 - C45-109 (#20)	Always	Below 1 Ω
No. 3	C7-2 - Body ground	Always	10 kΩ or higher
No. 3	C7-2 - C45-85 (#30)	Always	Below 1 Ω
No. 4	C14-2 - Body ground	Always	10 kΩ or higher
No. 4	C14-2 - C45-108 (#40)	Always	Below 1 Ω
No. 5	C9-2 - Body ground	Always	10 kΩ or higher
No. 5	C9-2 - C45-84 (#50)	Always	Below 1 Ω
No. 6	C12-2 - Body ground	Always	10 kΩ or higher
No. 6	C12-2 - C45-107 (#60)	Always	Below 1 Ω

for RHD
Cylinder	Tester Connection	Condition	Specified Condition
No. 1	C5-2 - Body ground	Always	10 kΩ or higher
No. 1	C5-2 - C46-86 (#10)	Always	Below 1 Ω
No. 2	C16-2 - Body ground	Always	10 kΩ or higher
No. 2	C16-2 - C46-109 (#20)	Always	Below 1 Ω
No. 3	C7-2 - Body ground	Always	10 kΩ or higher
No. 3	C7-2 - C46-85 (#30)	Always	Below 1 Ω
No. 4	C14-2 - Body ground	Always	10 kΩ or higher
No. 4	C14-2 - C46-108 (#40)	Always	Below 1 Ω
No. 5	C9-2 - Body ground	Always	10 kΩ or higher
No. 5	C9-2 - C46-84 (#50)	Always	Below 1 Ω
No. 6	C12-2 - Body ground	Always	10 kΩ or higher
No. 6	C12-2 - C46-107 (#60)	Always	Below 1 Ω

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

28.CHECK FUEL INJECTOR ASSEMBLY OF MISFIRING CYLINDER

Check the fuel injector injection [whether fuel volume is high or low, and whether injection pattern is poor] ().

REPLACE FUEL INJECTOR ASSEMBLY ()

OK

29.CHECK HARNESS AND CONNECTOR

Check the connection and terminal contact pressure of the connectors and wire harnesses between the mass air flow meter and ECM ().

HINT:

Repair any problems.

NEXT

30.CHECK WHETHER DTC OUTPUT RECURS

Connect the GTS to the DLC3.

Turn the ignition switch to ON.

Turn the GTS on.

Clear the DTCs ().

Turn the ignition switch off.

Turn the ignition switch to ON and turn the GTS on.

Start the engine and warm it up.

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.

Input the DTC: P0300, P0301, P0302, P0303, P0304, P0305 or P0306.

Check the DTC judgment result.

Result
Result	Proceed to
ABNORMAL (P0300, P0301, P0302, P0303, P0304, P0305 or P0306 is output)	A
NORMAL (No DTC is output)	B

END

A

31.CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)

Disconnect the mass air flow meter connector.

Disconnect the ECM connector.

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

Standard Resistance:
for LHD
Tester Connection Condition Specified Condition
C50-5 (VG) - C45-74 (VG) Always Below 1 Ω
C50-4 (E2G) - C45-75 (E2G) Always Below 1 Ω
C50-5 (VG) or C45-74 (VG) - Body ground Always 10 kΩ or higher
for RHD
Tester Connection Condition Specified Condition
C50-5 (VG) - C46-74 (VG) Always Below 1 Ω
C50-4 (E2G) - C46-75 (E2G) Always Below 1 Ω
C50-5 (VG) or C46-74 (VG) - Body ground Always 10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

32.REPLACE MASS AIR FLOW METER

Replace the mass air flow meter ().

HINT:

If the results of the inspections performed in steps 16 and 21 indicated no problem, proceed to the next step without replacing the mass air flow meter.

NEXT

33.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 ().

Turn the ignition switch off.

Turn the ignition switch to ON and turn the GTS on.

Start the engine and warm it up.

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.

Input the DTC: P0300, P0301, P0302, P0303, P0304, P0305 or P0306.

Check the DTC judgment result.

Result
Result	Proceed to
NORMAL (No DTC is output)	A
ABNORMAL (P0300, P0301, P0302, P0303, P0304, P0305 or P0306 is output)	B

REPLACE ECM ()

END

34.CHECK FUEL LINE

Check the fuel lines for leaks or blockage.

REPAIR OR REPLACE FUEL LINE

REPLACE FUEL PUMP ()

1GR-FE ENGINE CONTROL

Land Cruiser URJ200 URJ202 GRJ200 VDJ200

SFI SYSTEM