Inspection Procedure

HINT:

If DTCs besides misfire DTCs are memorized simultaneously, troubleshoot the non-misfire DTCs first.
If the misfire does not occur when the vehicle is brought to the workshop, the misfire can be confirmed by reproducing the condition of the freeze frame data. Also, after finishing the repair, confirm that there is no misfire (See confirmation driving pattern).
On 6 and 8 cylinder engines, misfiring cylinder identification is disabled at high engine speed and only a general misfire fault code P0300 is stored instead of a cylinder specific misfire fault code (P0301 to P0308).
If the misfire starts in a high engine speed area or the misfire occurs only in a high engine speed area, only code P0300 may be stored.

When only a general misfire fault code like P0300 is stored:
Erase the general misfire fault code from the hand-held tester or OBD II scan tool.
Start the engine and drive the confirmation pattern.
Read the value of the misfire ratio for each cylinder. Or read the DTC.
Perform repairs on the cylinder that has a high misfire ratio. Or repair the cylinder indicated by the DTC.
After finishing repairs, drive the confirmation pattern again and confirm that no misfire occurs.
When either of SHORT FT #1, LONG FT #1, SHORT FT #2 or LONG FT #2 in the freeze frame data is over the range of +/-20 %, there is a possibility that the air-fuel ratio is becoming RICH (-20 % or less) or LEAN (+20 % or more).
When COOLANT TEMP in the freeze frame data is less than 80°C (176°F), there is a possibility of misfire only during engine warm-up.
If the misfire cannot be reproduced, the following reasons may apply: 1) the vehicle has low fuel, 2) improper fuel is being used, and 3) the ignition plug is contaminated.
Be sure to check the value on the misfire counter after the repair.

Are there any other codes (besides DTC P0300, P0301, P0302, P0303, P0304 P0305, P0306, P0307 or P0308) being output?

PREPARATION:

Connect the hand-held tester or the OBD II scan tool to the DLC3.
Turn the ignition switch ON and push the hand-held tester or OBD II scan tool main switch ON.
When using hand-held tester, enter the following menus: DIAGNOSTICS / ENHANCED OBD II / DTC INFO / CURRENT CODES.

CHECK:

Read the DTC using hand-held tester or the OBD II scan tool.

RESULT:

DTC Output Display Table

Display (DTC Output)	Proceed to
"P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 and/or P0308"	A
"P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 or P0308" and other DTCs	B

HINT:

If any other codes besides "P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 or P0308" are output, perform the troubleshooting for those DTC.

B: Go to relevant DTC chart (See DIAGNOSTIC TROUBLE CODE CHART ).
A: Go to Next Step

Check wire harness, connector and vacuum hose in engine room.
CHECK:
1. Check the connection conditions of the wire harness and connector.
2. Check for the disconnection, piping and brake of the vacuum hose.
1. NG: Repair or replace, then confirm that there is no misfire (See confirmation driving pattern).
2. OK: Go to Next Step
Check connection of PCV piping.
1. NG: Repair or replace PCV piping.
2. OK: Go to Next Step

Connect hand-held tester, and read the number of misfire.

PREPARATION:

Connect the hand-held tester or the OBD II scan tool to the DLC3.
Turn the ignition switch ON and push the hand-held tester or the OBD II scan tool main switch ON.
Start the engine.
When using hand-held tester, enter the following menus: DIAGNOSTICS / ENHANCED OBD II / DATA LIST / ALL / CYL#1 to CYL#8.

CHECK:

Read the number of misfire on the hand-held tester or the OBD II scan tool.

HINT:

When a misfire is not reproduced, be sure to branch below based on the stored DTC.

RESULT:

Diagnostics -- High Misfire Rate Cylinder Table

High Misfire Rate Cylinder	Proceed to
1 or 2 cylinders	A
More than 3 cylinders	B

B: Go to step 15 .
A: Go to Next Step

Check spark plug and spark of misfiring cylinder.
PREPARATION:
1. Remove the ignition coil assembly.
2. Remove the spark plug.
CHECK:
1. Check the electrode for carbon deposits.
2. Check the spark plug type (See ON-VEHICLE INSPECTION ).
3. Check electrode gap.
OK:
1. No large carbon deposit present.
2. Not wet with gasoline or oil.
3. Electrode gap: 1.0 to 1.3 mm (0.039 to 0.051 in.)
Fig 1: Inspecting Spark Plug Electrode Gap
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NOTE: If adjusting the gap of a new spark plug, bend only "the base / ground" electrode. Do not touch the tip. Never attempt to adjust the gap on a used plug.

PREPARATION:
1. Install the spark plug to the ignition coil assembly.
2. Disconnect the injector connector.
3. Ground spark plug.
CHECK:

Check if spark occurs while engine is being cracked.

CAUTION: Always disconnect each injector connector.

NOTE: Do not crank the engine for more than 2 seconds.

OK:
1. Spark occurs across electrode gap.
1. OK: Go to step 8 .
2. NG: Go to Next Step
Change normal spark plug and check spark of misfiring cylinder.
PREPARATION:
1. Change to the normal spark plug.
  1. Remove the spark plug that may be faulty from the ignition coil assembly.
  2. Install the spark plug to the ignition coil assembly.
2. Disconnect the injector connector.
3. Ground the spark plug.
CHECK:

Check if spark occurs while the engine is being cranked.

CAUTION: Always disconnect each injector connector.

NOTE: Do not crank the engine for more than 2 seconds.

OK:
1. Spark jumps across electrode gap.
Fig 2: Inspecting For Spark At Spark Plug
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. OK: Replace spark plug.
2. NG: Go to Next Step

Check for open and short in harness and connector between ignition coil and ECM.

Check the harness and connector between the ignition coil and the ECM (IGF terminal) connectors:

PREPARATION:

Disconnect the I1, I2, I3, I4, I5, I6, I7 or I8 ignition coil connector.
Disconnect the E5 ECM connector.

CHECK:

Check the resistance between the wire harness side connectors.

OK:

Tester Connection Specified Condition Table

Tester Connection	Specified Condition
Ignition coil (I1-2) - IGF1 (E5-24)	Below 1 Ω
Ignition coil (I2-2) - IGF2 (E5-23)	Below 1 Ω
Ignition coil (I3-2) - IGF1 (E5-24)	Below 1 Ω
Ignition coil (I4-2) - IGF2 (E5-23)	Below 1 Ω
Ignition coil (I5-2) - IGF1 (E5-24)	Below 1 Ω
Ignition coil (I6-2) - IGF2 (E5-23)	Below 1 Ω
Ignition coil (I7-2) - IGF1 (E5-24)	Below 1 Ω
Ignition coil (I8-2) - IGF2 (E5-23)	Below 1 Ω
Ignition coil (I1-2) or IGF1 (E5-24) - Body ground	10 kΩ or higher
Ignition coil (I2-2) or IGF2 (E5-23) - Body ground	10 kΩ or higher
Ignition coil (I3-2) or IGF1 (E5-24) - Body ground	10 kΩ or higher
Ignition coil (I4-2) or IGF2 (E5-23) - Body ground	10 kΩ or higher
Ignition coil (I5-2) or IGF1 (E5-24) - Body ground	10 kΩ or higher
Ignition coil (I6-2) or IGF2 (E5-23) - Body ground	10 kΩ or higher
Ignition coil (I7-2) or IGF1 (E5-24) - Body ground	10 kΩ or higher
Ignition coil (I8-2) or IGF2 (E5-23) - Body ground	10 kΩ or higher

Fig 3: I1,I2,I3,I4,I5,I6,I7 or I8 Ignition Coil Connector

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 4: Disconnecting E5 ECM Connector

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Check the harness and connector between the ignition coil and the ECM (IGT terminal) connectors:

PREPARATION:

Disconnect the I1,I2,I3,I4,I5,I6,I7 or I8 ignition coil connector.
Disconnect the E5 ECM connector.

CHECK:

Check the resistance between the wire harness side connectors.

OK:

Tester Connection Specified Condition Table

Tester Connection	Specified Condition
Ignition coil (I1-3) - IGT1 (E5-9)	Below 1 Ω
Ignition coil (I2-3) - IGT2 (E5-8)	Below 1 Ω
Ignition coil (I3-3) - IGT3 (E5-25)	Below 1 Ω
Ignition coil (I4-3) - IGT4 (E5-11)	Below 1 Ω
Ignition coil (I5-3) - IGT5 (E5-12)	Below 1 Ω
Ignition coil (I6-3) - IGT6 (E5-26)	Below 1 Ω
Ignition coil (I7-3) - IGT7 (E5-13)	Below 1 Ω
Ignition coil (I8-3) - IGT8 (E5-10)	Below 1 Ω
Ignition coil (I1-3) or IGT1 (E5-9) - Body ground	10 kΩ or higher
Ignition coil (I2-3) or IGT2 (E5-8) - Body ground	10 kΩ or higher
Ignition coil (I3-3) or IGT3 (E5-25) - Body ground	10 kΩ or higher
Ignition coil (I4-3) or IGT4 (E5-11) - Body ground	10 kΩ or higher
Ignition coil (I5-3) or IGT5 (E5-12) - Body ground	10 kΩ or higher
Ignition coil (I6-3) or IGT6 (E5-26) - Body ground	10 kΩ or higher
Ignition coil (I7-3) or IGT7 (E5-13) - Body ground	10 kΩ or higher
Ignition coil (I8-3) or IGT8 (E5-10) - Body ground	10 kΩ or higher

Fig 5: I1, I2, I3, I4, I5, I6, I7 or I8 Ignition Coil Connector

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 6: Locating E5 ECM Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Replace ignition coil with igniter, then confirm that there is no misfire.
NG: Repair or replace harness or connector.

Check ECM terminal of misfiring cylinder.

PREPARATION:

Turn the ignition switch ON.

CHECK:

Measure the voltage between the terminals of the E5, E6 and E7 ECM connectors.

OK:

Tester Connection Specified Condition Table

Tester Connection	Specified Condition
#1 (E5-1) - E01 (E5-7)	9 to 14 V
#2 (E5-2) - E01 (E5-7)	9 to 14 V
#3 (E5-3) - E01 (E5-7)	9 to 14 V
#4 (E5-4) - E01 (E5-7)	9 to 14 V
#5 (E5-5) - E01 (E5-7)	9 to 14 V
#6 (E6-3) - E01 (E5-7)	9 to 14 V
#7 (E7-6) - E01 (E5-7)	9 to 14 V
#8 (E7-5) - E01 (E5-7)	9 to 14 V

Fig 7: Locating E5, E6 and E7 ECM Connector terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Go to step 11 .
NG: Go to Next Step

Check injector resistance of misfiring cylinder (See INJECTOR ).
1. NG: Replace injector.
2. OK: Go to Next Step

Check for open and short in harness and connector between ignition SW and injector, injector and ECM of misfiring cylinder.

Check the harness and the connector between the injector connector and the ECM connector:

PREPARATION:

Disconnect the I9, I10, I11, I12, I13, I14, I15 or I16 injector connector.
Disconnect the E5, E6 or E7 ECM connector.

CHECK:

Measure the resistance between the wire harness side connectors.

OK:

Tester Connection Specified Condition Table

Tester Connection	Specified Condition
Injector (I9-2) - #1 (E5-1)	Below 1 Ω
Injector (I10-2) - #2 (E5-2)	Below 1 Ω
Injector (I11-2) - #3 (E5-3)	Below 1 Ω
Injector (I12-2) - #4 (E5-4)	Below 1 Ω
Injector (I13-2) - #5 (E5-5)	Below 1 Ω
Injector (I14-2) - #6 (E6-3)	Below 1 Ω
Injector (I15-2) - #7 (E7-6)	Below 1 Ω
Injector (I16-2) - #8 (E7-5)	Below 1 Ω
Injector (I9-2) or #1 (E5-1) - Body ground	10 kΩ or higher
Injector (I10-2) or #2 (E5-2) - Body ground	10 kΩ or higher
Injector (I11-2) or #3 (E5-3) - Body ground	10 kΩ or higher
Injector (I12-2) or #4 (E5-4) - Body ground	10 kΩ or higher
Injector (I13-2) or #5 (E5-5) - Body ground	10 kΩ or higher
Injector (I14-2) or #6 (E6-3) - Body ground	10 kΩ or higher
Injector (I15-2) or #7 (E7-6) - Body ground	10 kΩ or higher
Injector (I16-2) or #8 (E7-5) - Body ground	10 kΩ or higher

Fig 8: Identifying Injector Connector terminal

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 9: Disconnecting E5, E6 or E7 ECM Connector

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 10: Identifying 118 Ignition Switch Connector terminals IG2

Check the harness and connector between the injector connector and the ignition switch:

PREPARATION:

Disconnect the I9, I10, I11, I12, I13, I14, I15 or I16 injector connector.
Disconnect the I18 ignition switch connector.

CHECK:

Measure the resistance between the wire harness side connectors.

OK:

Tester Connection Specified Condition Table

Tester Connection	Specified Condition
Injector (I9-1) - IG2 (I18-6)	Below 1 Ω
Injector (I10-1) - IG2 (I18-6)	Below 1 Ω
Injector (I11-1) - IG2 (I18-6)	Below 1 Ω
Injector (I12-1) - IG2 (I18-6)	Below 1 Ω
Injector (I13-1) - IG2 (I18-6)	Below 1 Ω
Injector (I14-1) - IG2 (I18-6)	Below 1 Ω
Injector (I15-1) - IG2 (I18-6)	Below 1 Ω
Injector (I16-1) - IG2 (I18-6)	Below 1 Ω
Injector (I9-1) or IG2 (I18-6) Body ground	10 Ω or higher
Injector (I10-1) or IG2 (I18-6) Body ground	10 Ω or higher
Injector (I11-1) or IG2 (I18-6) Body ground	10 Ω or higher
Injector (I12-1) or IG2 (I18-6) Body ground	10 Ω or higher
Injector (I13-1) or IG2 (I18-6) Body ground	10 Ω or higher
Injector (I14-1) or IG2 (I18-6) Body ground	10 Ω or higher
Injector (I15-1) or IG2 (I18-6) Body ground	10 Ω or higher
Injector (I16-1) or IG2 (I18-6) Body ground	10 Ω or higher

NG: Repair or replace harness or connector.
OK: Go to Next Step

Check injector injection of misfiring cylinder (See inspection under INJECTOR ).
1. NG: Replace injector.
2. OK: Go to Next Step
Check compression pressure of misfiring cylinder (See COMPRESSION ).
1. NG: Repair or replace.
2. OK: Go to Next Step
Check valve clearance of misfiring cylinder (See VALVE CLEARANCE ).
1. NG: Adjust valve clearance.
2. OK: Go to Next Step

Check result of step 4 switch step by number of misfire cylinder.

Misfire Cylinder Table

High misfire rate cylinder	Proceed to
1 or 2 cylinders	A
More than 3 cylinders	B

B: Check for intermittent problems (See PRE-CHECK ).
A: Go to Next Step

Check valve timing (Check for looseness or a jumped tooth of timing belt) (See TIMING BELT ).
1. NG: Adjust valve timing (Repair or replace timing belt).
2. OK: Go to Next Step
Check fuel pressure (See ON-VEHICLE INSPECTION ).
1. NG: Check and repair fuel pump, pressure regulator, fuel pipe line and filter (See SFI SYSTEM ).
2. OK: Go to Next Step

Check intake air temperature and mass air flow rate.

PREPARATION:

Connect the hand-held tester or the OBD II scan tool to the DLC3.
Turn the ignition switch ON.

CHECK:

Check the intake air temperature.

Select the item "DIAGNOSTICS/ENHANCED OBD II/DATA LIST/ALL/INTAKE AIR".
Read its value displayed on the hand-held tester or the OBD II scan tool.

OK:

Equivalent to ambient temperature

CHECK:

Check the air flow rate.

Select the item "DIAGNOSTICS/ENHANCED OBD II/DATA LIST/ALL/MAF".
Read its value displayed on the hand-held tester or the OBD II scan tool.

OK:

Engine Condition and Air Flow Rate Table

Condition	Air Flow Rate (gm/s)
Ignition switch ON (do not start engine)	0
Idling	4 to 6
Running without load (2,500 RPM)	13 to 20
Idling to quickly accelerating	Air flow rate fluctuates

NG: Replace mass air flow meter.
OK: Go to Next Step

Check engine coolant temperature sensor.
PREPARATION:

Remove the engine coolant temperature sensor.

CHECK:

Measure the resistance between the terminals of the engine coolant temperature sensor.
1. Resistance:
  
  Fig 11: Tester Connection Specified Condition Table
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NOTE: In case of checking the engine coolant temperature sensor in the water, be careful not to allow water to go into the terminals. After checking, dry the sensor.

HINT:

Alternate procedure: Connect an ohmmeter to the installed engine coolant temperature sensor and read the resistance. Use an infrared thermometer to measure the engine temperature in the immediate vicinity of the sensor. Compare these values to the resistance/temperature graph. Change the engine temperature (warm up or allow to cool down) and repeat the test.

Fig 12: Measuring Resistance Between Terminals Of Engine Coolant Temperature Sensor
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: Replace engine coolant temperature sensor.
2. OK: Go to Next Step

Switch step by number of misfire cylinder (Refer result of step 4).

Misfire cylinder Table

High misfire rate cylinder	Proceed to
1 or 2 cylinders	A
More than 3 cylinders	B

B: Go to step 5 .
A: Check for intermittent problems (See PRE-CHECK ).