SFI SYSTEM, Diagnostic DTC:P0300, P0301, P0302, P0303, 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.	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 sub-assembly Engine coolant temperature sensor Compression pressure Valve timing PCV valve and hose PCV hose connections Intake system Intake air control valve actuator (for tumble control valve) ECM
P0301 P0302 P0303 P0304	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).

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 sub-assembly
Engine coolant temperature sensor
Compression pressure
Valve timing
PCV valve and hose
PCV hose connections
Intake system
Intake air control valve actuator (for tumble control valve)
ECM

P0301

P0302

P0303

P0304

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 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 either one of the following conditions, which could cause emission deterioration, is detected (2 trip detection logic).

Within the first 1000 crankshaft revolutions after the engine starts, an excessive number of misfires (approximately 10 to 70 misfires per 1000 crankshaft revolutions) occurs once.
An excessive number of misfires (approximately 10 to 70 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.

At a high engine speed, a sufficient amount of misfires to damage the catalyst occurring within 200 crankshaft revolutions is detected once.
At a normal engine speed, a sufficient amount of misfires to damage the catalyst occurring within 200 crankshaft revolutions is detected 3 times.

Misfire Monitor for Mexico Models

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 after the engine starts, an excessive number of misfires (approximately 500 misfires per 1000 crankshaft revolutions) occurs once.
An excessive number of misfires (approximately 250 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 condition, which could cause the three-way catalytic converter damage, is detected.

A catalyst-damaging misfire, which is monitored every 200 crankshaft revolutions, occurs 3 times.

MONITOR STRATEGY

Related DTCs	P0300: Multiple cylinder misfire P0301: Cylinder 1 misfire P0302: Cylinder 2 misfire P0303: Cylinder 3 misfire P0304: Cylinder 4 misfire
Required Sensors/Components (Main)	Crankshaft position sensor Camshaft position sensor
Required Sensors/Components (Related)	Engine coolant temperature Intake air temperature sensor Mass air flow meter sub-assembly
Frequency of Operation	Continuous
Duration	1000 crankshaft revolutions (soon after engine is started: 1 time, other 4 times) (Emission-related misfire) 200 crankshaft revolutions (1 or 3 times) (Catalyst-damaging misfire)
MIL Operation	2 driving cycles: Emission-related misfire MIL flashes immediately: Catalyst-damaging misfire
Sequence of Operation	None

TYPICAL ENABLING CONDITIONS

Misfire
Monitor runs whenever the following DTCs are not stored	P0016 (VVT system - misalignment) P0017 (Exhaust VVT system - misalignment) P0102, P0103 (Mass air flow meter) P0112, P0113 (Intake air temperature sensor) P0115, P0117, P0118 (Engine coolant temperature sensor) P0120, P0121, P0122, P0123, P0220, P0222, P0223, P2135 (Throttle position sensor) P0125 (Insufficient coolant temperature for closed loop fuel control) P0327, P0328 (Knock control sensor) P0335 (Crankshaft position sensor) P0340, P0342, P0343 (Camshaft position sensor) P0351 - P0354 (Igniter) P0500 (Vehicle speed sensor) P0705 (Shift lever position switch)
Battery voltage	8 V or higher
VVT system	Not operated by scan tool
Engine speed	400 to 6300 rpm
Either of the following conditions is met	A or B
A. Engine coolant temperature at engine start	Higher than -7°C (19°F)
B. Engine coolant temperature	Higher than 20°C (68°F)
Fuel cut	Off

Monitor Period of Emission-related Misfire
First 1000 revolutions after engine start, or during check mode	Crankshaft 1000 revolutions
Except above	Crankshaft 1000 revolutions x 4

Monitor Period of Catalyst-damaging Misfire (MIL Blinks)
All of the following conditions 1, 2, 3 and 4 met	Crankshaft 200 revolutions x 3
Except above (MIL blinks immediately)	Crankshaft 200 revolutions
1. Driving cycles	1st
2. Check mode	Off
3. Engine speed	Less than 2150 rpm
4. Intake air amount per revolution	Less than 0.95 g/rev

Misfire: for Mexico Models
Monitor runs whenever the following DTCs are not stored	P0016 (VVT system - misalignment) P0017 (Exhaust VVT system - misalignment) P0102, P0103 (Mass air flow meter) P0112, P0113 (Intake air temperature sensor) P0115, P0117, P0118 (Engine coolant temperature sensor) P0120, P0121, P0122, P0123, P0220, P0222, P0223, P2135 (Throttle position sensor) P0125 (Insufficient coolant temperature for closed loop fuel control) P0327, P0328 (Knock control sensor) P0335 (Crankshaft position sensor) P0340, P0342, P0343 (Crankshaft position sensor) P0351 - P0354 (Igniter) P0500 (Vehicle speed sensor) P0705 (Shift lever position switch)
Battery voltage	8 V or higher
VVT system	Not operated by scan tool
Engine speed	400 to 6300 rpm
Engine coolant temperature	Higher than 65°C (149°F)
Fuel cut	Off

Monitor Period of Emission-related Misfire: for Mexico Models
First 1000 revolutions after engine start, or check mode	Crankshaft 1000 revolutions
Except above	Crankshaft 1000 revolutions x 4

Monitor Period of Catalyst-damaging Misfire (MIL Blinks): for Mexico Models
Both of the following conditions 1 and 2 met:	Crankshaft 200 revolutions x 3
1. Driving cycles	1st
2. Check mode	Off
Except above (MIL blinks immediately)	Crankshaft 200 revolutions

TYPICAL MALFUNCTION THRESHOLDS

Monitor Period of Emission-related Misfire
Misfire rate	1.493% or higher (except PZEV) 1.12% or higher (for PZEV)

Monitor Period of Catalyst-damaging Misfire (MIL Blinks)
Number of misfires per 200 revolutions	130 or more (varies with intake air amount and engine speed) (except PZEV) 118 or more (varies with intake air amount and engine speed) (for PZEV)

Monitor Period of Emission-related Misfire: for Mexico Models
Misfire rate	50% or higher: for 1st 1000 revolutions 25% or higher: after 1st 1000 revolutions

Monitor Period of Catalyst-damaging Misfire (MIL Blinks): for Mexico Models
Number of misfires per 200 revolutions	130 or more (varies with intake air amount and engine speed)

MONITOR RESULT

Refer to detailed information in Checking Monitor Status Click here.

P0300: Misfire / EWMA MISFIRE
Monitor ID	Test ID	Scaling	Unit	Description
$A1	$0B	Multiply by 1	Time	Total EWMA* misfire count of all cylinders in last ten driving cycles

P0300: Misfire / MISFIRE RATE
Monitor ID	Test ID	Scaling	Unit	Description
$A1	$0C	Multiply by 1	Time	When ignition switch is ON, total misfire count of all cylinders in last driving cycle is displayed. While engine is running, total misfire count of all cylinders in current driving cycle is displayed.

P0301: Misfire / EWMA MISFIRE1
Monitor ID	Test ID	Scaling	Unit	Description
$A2	$0B	Multiply by 1	Time	Total EWMA* misfire count of cylinder 1 in last ten driving cycles

P0301: Misfire / MISFIRE RATE1
Monitor ID	Test ID	Scaling	Unit	Description
$A2	$0C	Multiply by 1	Time	When ignition switch is ON, total misfire count of cylinder 1 in last driving cycle is displayed. While engine is running, total misfire count of cylinder 1 in current driving cycle is displayed.

P0302: Misfire / EWMA MISFIRE2
Monitor ID	Test ID	Scaling	Unit	Description
$A3	$0B	Multiply by 1	Time	Total EWMA* misfire count of cylinder 2 in last ten driving cycles

P0302: Misfire / MISFIRE RATE2
Monitor ID	Test ID	Scaling	Unit	Description
$A3	$0C	Multiply by 1	Time	When ignition switch is ON, total misfire count of cylinder 2 in last driving cycle is displayed. While engine is running, total misfire count of cylinder 2 in current driving cycle is displayed.

P0303: Misfire / EWMA MISFIRE3
Monitor ID	Test ID	Scaling	Unit	Description
$A4	$0B	Multiply by 1	Time	Total EWMA* misfire count of cylinder 3 in last ten driving cycles

P0303: Misfire / MISFIRE RATE3
Monitor ID	Test ID	Scaling	Unit	Description
$A4	$0C	Multiply by 1	Time	When ignition switch is ON, total misfire count of cylinder 3 in last driving cycle is displayed. While engine is running, total misfire count of cylinder 3 in current driving cycle is displayed.

P0304: Misfire / EWMA MISFIRE4
Monitor ID	Test ID	Scaling	Unit	Description
$A5	$0B	Multiply by 1	Time	Total EWMA* misfire count of cylinder 4 in last ten driving cycles

P0304: Misfire / MISFIRE RATE4
Monitor ID	Test ID	Scaling	Unit	Description
$A5	$0C	Multiply by 1	Time	When ignition switch is ON, total misfire count of cylinder 4 in last driving cycle is displayed. While engine is running, total misfire count of cylinder 4 in current driving cycle is displayed.

Tech Tips

*: EWMA (Exponential Weighted Moving Average) misfire counts for last 10 driving cycles (calculated) Calculation: 0.1 x (current counts) + 0.9 x (previous average) Initial value for (previous average) = 0

CONFIRMATION DRIVING PATTERN

Connect the Techstream to the DLC3.
Turn the ignition switch to ON.
Turn the Techstream on.
Record the DTC(s) and freeze frame data.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Using the Techstream, 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.

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, confirm the Misfire RPM and Misfire Load in the Data List.

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.

Tech Tips

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.
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.

INSPECTION PROCEDURE

Note

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

Tech Tips

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 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 higher).
When Coolant Temp in the freeze frame data is below 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 Techstream to the DLC3.
Turn the ignition switch to ON.
Turn the Techstream on.
Enter the following menus: 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

Tech Tips

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

GO TO DTC CHART Click here

CHECK PCV HOSE CONNECTIONS
1. Check the PCV hose connections Click here.
  
  OK
  
  PCV valve and hose are correctly connected and are not damaged.
NG
REPAIR OR REPLACE PCV HOSE

OK
READ VALUE USING TECHSTREAM (MISFIRE RPM AND MISFIRE LOAD)
1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the Techstream on.
4. Enter the following menus: Powertrain / Engine and ECT / Data List / Gas Misfire / Misfire RPM and Misfire Load.
5. 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

OK
PCV valve and hose are correctly connected and are not damaged.

READ VALUE USING TECHSTREAM (CATALYST OT MF F/C)

Connect the Techstream to the DLC3.
Turn the ignition switch to ON.
Turn the Techstream on.
Enter the following menus: Powertrain / Engine and ECT / Data List / Gas Misfire / Catalyst OT MF F/C.

Read the value displayed on the Techstream.

Result
Data List	Techstream Display	Proceed to
Catalyst OT MF F/C	Avail	A
Catalyst OT MF F/C	Not Avl	B

READ VALUE USING TECHSTREAM (CYLINDER MISFIRE COUNT) Click here

PERFORM ACTIVE TEST USING TECHSTREAM (PROHIBIT THE CATALYST OT MISFIRE PREVENT F/C)
1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the Techstream on.
4. Enter the following menus: Powertrain / Engine and ECT / Active Test / Prohibit the Catalyst OT Misfire Prevent F/C.
5. Perform the Active Test.
  
  Note
  
  When performing the Active Test, make sure the vehicle is stopped and the engine is either idling or being revved within 3000 rpm.
NEXT

READ VALUE USING TECHSTREAM (CYLINDER MISFIRE COUNT)

Connect the Techstream to the DLC3.
Turn the ignition switch to ON.
Turn the Techstream on.
Enter the following menus: Powertrain / Engine and ECT / Data List / Gas Misfire / Cylinder #1 Misfire Count, Cylinder #2 Misfire Count, Cylinder #3 Misfire Count and 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 Techstream. 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 Techstream (Misfire RPM and Misfire Load)" procedures above [A].

Read the Cylinder #1 Misfire Count to Cylinder #4 Misfire Count or DTCs displayed on the Techstream [B].

Result
Result	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 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.

CHECK INTAKE SYSTEM Click here

INSPECT SPARK PLUG
1. Inspect the spark plug of the misfiring cylinder Click here.
  
  Tech Tips
  
  Perform "Inspection After Repair" after replacing the spark plug Click here.
NG
REPLACE SPARK PLUG Click here

OK
CHECK FOR SPARK (SPARK TEST)
1. Perform a spark test Click here.
  Tech Tips
  - 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.
NEXT
CHECK CYLINDER COMPRESSION PRESSURE
1. Measure the cylinder compression pressure of the misfiring cylinder Click here.
  
  Tech Tips
  
  Perform "Inspection After Repair" after repairing or replacing the engine assembly Click here.
NG
CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

OK

CHECK TERMINAL VOLTAGE (POWER SOURCE OF FUEL INJECTOR ASSEMBLY)

Text in Illustration

*a
Front view of wire harness connector

(to ECM)

Disconnect the ECM connector.
Turn the ignition switch to ON.

Text in Illustration
*a	Front view of wire harness connector (to ECM)

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

Standard Voltage

Tester Connection	Switch Condition	Specified Condition
E26-20 (#10) - E26-50 (E01)	Ignition switch ON	11 to 14 V
E26-17 (#20) - E26-50 (E01)	Ignition switch ON	11 to 14 V
E26-18 (#30) - E26-50 (E01)	Ignition switch ON	11 to 14 V
E26-19 (#40) - E26-50 (E01)	Ignition switch ON	11 to 14 V

CHECK FUEL INJECTOR CIRCUIT Click here

CHECK FUEL INJECTOR OF MISFIRING CYLINDER
1. Check the fuel injector assembly injection (whether fuel volume is high or low, and whether injection pattern is poor) Click here.
  
  Tech Tips
  
  Perform "Inspection After Repair" after replacing the fuel injector assembly Click here.
NG
REPLACE FUEL INJECTOR ASSEMBLY Click here

OK
CHECK INTAKE SYSTEM
1. Check the intake system for vacuum leaks Click here.
  
  OK
  
  No leaks from intake system.
  
  Tech Tips
  
  Perform "Inspection After Repair" after repairing or replacing the intake system Click here.
NG
REPAIR OR REPLACE INTAKE SYSTEM

OK
CHECK INTAKE AIR CONTROL VALVE ACTUATOR (FOR TUMBLE CONTROL VALVE)
1. Check the intake air control valve actuator (for tumble control valve) Click here.
NG
REPLACE INTAKE AIR CONTROL VALVE ACTUATOR (FOR TUMBLE CONTROL VALVE) Click here

OK
CHECK FUEL PRESSURE
1. Check the fuel pressure Click here.
NG
CHECK FUEL LINE Click here

OK

READ VALUE USING TECHSTREAM (COOLANT TEMP)

Connect the Techstream to the DLC3.
Turn the ignition switch to ON.
Turn the Techstream on.
Enter the following menus: Powertrain / Engine and ECT / Data List / Primary / Coolant Temp.

Read the Data List twice, when the engine is both cold and warmed up.

Standard

Techstream Display	Condition	Specified Condition
Coolant Temp	Cold engine	Same as ambient air temperature
Coolant Temp	Warm engine	Between 75 and 100°C (167 and 212°F)

Tech Tips

Perform "Inspection After Repair" after replacing the engine coolant temperature sensor Click here.

REPLACE ENGINE COOLANT TEMPERATURE SENSOR Click here

READ VALUE USING TECHSTREAM (MAF)

Connect the Techstream to the DLC3.
Turn the ignition switch to ON.
Turn the Techstream on.
Enter the following menus: Powertrain / Engine and ECT / Data List / Primary / MAF, Coolant Temp and Engine Speed.
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

Techstream Display

Condition

Specified Condition

MAF

Shift lever position: N

A/C: Off

Engine Speed: 3000 rpm

Between 8 gm/sec and 22 gm/sec

CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY CONNECTOR CONNECTION) Click here

CHECK VALVE TIMING (CHECK FOR LOOSE TIMING CHAIN AND JUMPED TEETH)

Text in Illustration
*1	Timing Mark	-	-

Remove the cylinder head cover sub-assembly.
Turn the crankshaft pulley and align its groove with the "0" timing mark of the timing chain cover.

Check that the timing marks of the camshaft timing gear assembly and camshaft timing exhaust gear assembly are at the positions shown in the illustration.

Tech Tips

If the timing marks are not as shown, turn the crankshaft one revolution clockwise.

OK
Timing marks on camshaft timing gear assembly and camshaft timing exhaust gear assembly are aligned as shown in the illustration.

CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY CONNECTOR CONNECTION) Click here

ADJUST VALVE TIMING Click here

CHECK INTAKE SYSTEM
1. Check the intake system for vacuum leaks Click here.
  
  OK
  
  No leaks from intake system.
  
  Tech Tips
  
  Perform "Inspection After Repair" after repairing or replacing the intake system Click here.
NG
REPAIR OR REPLACE INTAKE SYSTEM

OK
CHECK INTAKE AIR CONTROL VALVE ACTUATOR (FOR TUMBLE CONTROL VALVE)
1. Check the intake air control valve actuator (for tumble control valve) Click here.
NG
REPLACE INTAKE AIR CONTROL VALVE ACTUATOR (FOR TUMBLE CONTROL VALVE) Click here

OK
CHECK FUEL PRESSURE
1. Check the fuel pressure Click here.
NG
CHECK FUEL LINE Click here

OK

READ VALUE USING TECHSTREAM (COOLANT TEMP)

Connect the Techstream to the DLC3.
Turn the ignition switch to ON.
Turn the Techstream on.
Enter the following menus: Powertrain / Engine and ECT / Data List / Primary / Coolant Temp.

Read the Data List twice, when the engine is both cold and warmed up.

Standard

Techstream Display	Condition	Specified Condition
Coolant Temp	Cold engine	Same as ambient air temperature
Coolant Temp	Warm engine	Between 75 and 100°C (167 and 212°F)

Tech Tips

Perform "Inspection After Repair" after replacing the engine coolant temperature sensor Click here.

REPLACE ENGINE COOLANT TEMPERATURE SENSOR Click here

READ VALUE USING TECHSTREAM (MAF)

Connect the Techstream to the DLC3.
Turn the ignition switch to ON.
Turn the Techstream on.
Enter the following menus: Powertrain / Engine and ECT / Data List / Primary / MAF, Coolant Temp and Engine Speed.
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

Techstream Display

Condition

Specified Condition

MAF

Shift lever position: N

A/C: Off

Engine Speed: 3000 rpm

Between 8 gm/sec and 22 gm/sec

CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY CONNECTOR CONNECTION) Click here

CHECK VALVE TIMING (CHECK FOR LOOSE TIMING CHAIN AND JUMPED TEETH)

Text in Illustration
*1	Timing Mark	-	-

Remove the cylinder head cover sub-assembly.
Turn the crankshaft pulley and align its groove with the "0" timing mark of the timing chain cover.

Check that the timing marks of the camshaft timing gear assembly and camshaft timing exhaust gear assembly are at the positions shown in the illustration.

Tech Tips

If the timing marks are not as shown, turn the crankshaft one revolution clockwise.

OK
Timing marks on camshaft timing gear assembly and camshaft timing exhaust gear assembly are aligned as shown in the illustration.

ADJUST VALVE TIMING Click here

INSPECT SPARK PLUG
1. Inspect the spark plug of the misfiring cylinder Click here.
  
  Tech Tips
  
  Perform "Inspection After Repair" after replacing the spark plug Click here.
NG
REPLACE SPARK PLUG Click here

OK
CHECK FOR SPARK (SPARK TEST)
1. Perform a spark test Click here.
  Tech Tips
  - 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.
NEXT
CHECK CYLINDER COMPRESSION PRESSURE
1. Measure the cylinder compression pressure of the misfiring cylinder Click here.
  
  Tech Tips
  
  Perform "Inspection After Repair" after repairing or replacing the engine assembly Click here.
NG
CHECK ENGINE TO DETERMINE CAUSE OF LOW COMPRESSION

OK

CHECK TERMINAL VOLTAGE (POWER SOURCE OF FUEL INJECTOR ASSEMBLY)

Text in Illustration

*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	Switch Condition	Specified Condition
E26-20 (#10) - E26-50 (E01)	Ignition switch ON	11 to 14 V
E26-17 (#20) - E26-50 (E01)	Ignition switch ON	11 to 14 V
E26-18 (#30) - E26-50 (E01)	Ignition switch ON	11 to 14 V
E26-19 (#40) - E26-50 (E01)	Ignition switch ON	11 to 14 V

CHECK FUEL INJECTOR CIRCUIT Click here

CHECK FUEL INJECTOR OF MISFIRING CYLINDER
1. Check the fuel injector assembly injection (whether fuel volume is high or low, and whether injection pattern is poor) Click here.
  
  Tech Tips
  
  Perform "Inspection After Repair" after replacing the fuel injector assembly Click here.
NG
REPLACE FUEL INJECTOR ASSEMBLY Click here

OK
CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY CONNECTOR CONNECTION)
1. Check the connection and terminal contact pressure of connectors and wire harnesses between the mass air flow meter sub-assembly and ECM Click here.
  
  Tech Tips
  
  Repair any problems.
NEXT

CHECK WHETHER DTC OUTPUT RECURS (MISFIRE DTCS)

Connect the Techstream to the DLC3.
Turn the ignition switch to ON.
Turn the Techstream on.
Clear the DTCs Click here.
Turn the ignition switch off and wait for at least 30 seconds.
Turn the ignition switch to ON.
Turn the Techstream 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 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

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
E14-5 (VG) - E26-91 (VG)	Always	Below 1 Ω
E14-4 (E2G) - E26-92 (E2G)	Always	Below 1 Ω
E14-5 (VG) or E26-91 (VG) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

REPLACE MASS AIR FLOW METER SUB-ASSEMBLY
1. Replace the mass air flow meter sub-assembly Click here.
  Tech Tips
  - 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 sub-assembly.
  - Perform "Inspection After Repair" after replacing the mass air flow meter sub-assembly Click here.
NEXT

CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

Connect the Techstream to the DLC3.
Turn the ignition switch to ON.
Turn the Techstream on.
Clear the DTCs Click here.
Turn the ignition switch off and wait for at least 30 seconds.
Turn the ignition switch to ON.
Turn the Techstream 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 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

REPLACE ECM Click here

END

CHECK FUEL LINE
1. Check the fuel lines for leaks or blockage.
  
  Tech Tips
  
  Perform "Inspection After Repair" after replacing the fuel pump Click here.
NG
REPAIR OR REPLACE FUEL LINE

OK

REPLACE FUEL PUMP Click here