Inspection Procedure

WARNING: This page is about a different car, the 2004 Toyota Corolla. However, it is still accessible from the selected car via links, so may be relevant.

HINT:

If DTCs besides misfire are memorized simultaneously, first perform the troubleshooting for them.
Read freeze frame data using the hand-held tester or the OBD II scan tool. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.
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. After finishing the repair, confirm that there is no misfire (See CONFIRMATION DRIVING PATTERN ).
When either of SHORT FT #1 or LONG FT #1 in the freeze frame data is over the range of +/-20 %, there is a possibility that the air-fuel ratio is inclining either to 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 reason may be because of the driving the vehicle with lack of fuel, the use of improper fuel, a stain on the ignition plug, etc.
Be sure to check the value on the misfire counter after the repair.

CHECK OTHER DTC OUTPUT (IN ADDITION TO MISFIRE DTCS)

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.
Select the item "DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES".

Read the DTCs.

Result:

RESULT REFERENCE

Display (DTC output)	Proceed to
"P0300, P0301, P0302, P0303 and/or P0304"	A
"P0300, P0301, P0302, P0303 and/or P0304" and other DTCs	B

HINT:

If any other codes besides P0300, P0301, P0302, P0303 or P0304 are output, perform the troubleshooting for those DTCs first.

B : GO TO RELEVANT DIAGNOSTIC TROUBLE CODE CHART
A : GO TO NEXT STEP

CHECK WIRE HARNESS, CONNECTOR AND VACUUM HOSE IN ENGINE ROOM
1. Check the connection conditions of the wire harness and connector.
2. Check the vacuum hose piping for disconnection and break.
- NG : REPAIR OR REPLACE, THEN CONFIRM THAT THERE IS NO MISFIRE
- OK : GO TO NEXT STEP
CHECK CONNECTION OF PCV HOSE
- NG : REPAIR OR REPLACE PCV HOSE
- OK : GO TO NEXT STEP

READ VALUE OF HAND-HELD TESTER OR OBD II SCAN TOOL (NUMBER OF MISFIRE

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.
Select the item "DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / CYL#1 - CYL#4".
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:

RESULT REFERENCE

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

Remove the ignition coil assembly.
Remove the spark plug.

Check the spark plug type.

Recommended spark plug:

DENSO MADE REFERENCE

DENSO made	SK16R11
NGK made	IFR5A11

Check the spark plug electrode gap.

Fig 1: Checking Spark Plug Electrode Gap
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Electrode gap: 1.0 to 1.3 mm (0.039 to 0.051 in.)

NOTE: If adjusting the gap of a new spark plug, bend only the base of the ground electrode. Do not touch the tip. Never attempt to adjust the gap on a used plug.
Check the electrode for carbon deposits.
Perform a spark test.
CAUTION: Absolutely disconnect the each injector connectors.

NOTE: Do not crank the engine for more than 5 seconds at a time.
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 spark occurs while the engine is being cranked.
Standard: Spark jumps across electrode gap.
Reinstall the spark plug.
Reinstall the ignition coil assy.

OK : Go to step 8
NG : GO TO NEXT STEP

CHANGE NORMAL SPARK PLUG AND CHECK SPARK OF MISFIRING CYLINDER
1. Change to the normal spark plug.
2. Perform a spark test.
CAUTION: Absolutely disconnect each injector connector.

NOTE: Do not crank the engine for more than 5 seconds at a time.
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 spark occurs while the engine is being cranked.
Standard: Spark jumps across electrode gap.
- OK : REPLACE SPARK PLUG
- NG : GO TO NEXT STEP

CHECK HARNESS AND CONNECTOR OF MISFIRING CYLINDER (IGNITION COIL - ECM)

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

Disconnect the I2, I3, I4 or I5 ignition coil and igniter connector.
Disconnect the ECM E3 connector.

Check the resistance between the wire harness side connectors.

Fig 2: Identifying ECM E3 Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Standard (Check for open):

TESTER CONNECTION AND SPECIFIED CONDITION

Tester Connection	Specified Condition
IGF(I2-2)-IGF(E3-23)	Below 1 Ω
IGF(I3-2)-IGF(E3-23)
IGF(I4-2)-IGF(E3-23)
IGF(I5-2)-IGF(E3-23)

Standard (Check for short):

TESTER CONNECTION AND SPECIFIED CONDITION

Tester Connection	Specified Condition
IGF (I2-2) or IGF (E3-23) - Body ground	10 kΩ or higher
IGF (I3-2) or IGF (E3-23) - Body ground
IGF (I4-2) or IGF (E3-23) - Body ground
IGF (I5-2) or IGF (E3-23) - Body ground

Fig 3: Identifying Ignition Coil And Igniter Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Reconnect the ECM connector.
Reconnect the ignition coil and igniter connector.

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

Disconnect the I2, I3, I4 or I5 ignition coil and igniter connector.
Disconnect the ECM E3 connector.

Check the resistance between the wire harness side connectors.

Fig 4: Identifying ECM E3 Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Standard (Check for open):

TESTER CONNECTION AND SPECIFIED CONDITION

Tester Connection	Specified Condition
IGT (I2-3) - IGT1 (E3-8)	Below 1Ω
IGT (I3-3) - IGT2 (E3-9)
IGT (I4-3) - IGT3 (E3-10)
IGT (I5-3) - IGT4 (E3-11)

Standard (Check for short):

Fig 5: Identifying Ignition Coil And Igniter Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

TESTER CONNECTION AND SPECIFIED CONDITION

Tester Connection	Specified Condition
IGT (I2-3) or IGT1 (E3-8) - Body ground	10 kΩ or higher
IGT (I3-3) or IGT2 (E3-9) - Body ground
IGT (I4-3) or IGT3 (E3-10) - Body ground
IGT (I5-3) or IGT4 (E3-11) - Body ground

Reconnect the ECM connector.
Reconnect the ignition coil and igniter connector.

OK : REPLACE IGNITION COIL ASSY (THEN CONFIRM THAT THERE IS NO MISFIRE)
NG : REPAIR OR REPLACE HARNESS OR CONNECTOR

: INSPECT ECM TERMINAL OF MISFIRING CYLINDER(#10, #20, #30 OR #40 VOLTAGE)

Turn the ignition switch ON.

Measure the voltage between the terminals of the E3 ECM connector.

Standard:

SPECIFIED CONDITION

Symbols (Terminal No.)	Specified Condition
#10 (E3-1) - E01 (E3-7)	8 to 14 V
#20 (E3-2) - E01 (E3-7)
#30 (E3-3) - E01 (E3-7)
#40 (E3-4) - E01 (E3-7)

Fig 6: Identifying E3 ECM Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK : Go to step 11
NG : GO TO NEXT STEP

: INSPECT FUEL INJECTOR RESISTANCE OF MISFIRING CYLINDER (See INSPECTION )
- NG : REPLACE FUEL INJECTOR ASSY (See REPLACEMENT )
- OK : GO TO NEXT STEP

CHECK HARNESS AND CONNECTOR OF MISFIRING CYLINDER (INJECTOR - ECM, INJECTOR - IGNITION SWITCH)

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

Disconnect the I6, I7, I8 or I9 injector connector.
Disconnect the E3 ECM connector.

Measure the resistance between the wire harness side connectors.

Fig 7: Identifying Injector Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Standard (Check for open):

TESTER CONNECTION AND SPECIFIED CONDITION

Tester Connection	Specified Condition
Injector (I6-2) - #10 (E3-1)	Below 1 Ω
Injector (I7-2) - #20 (E3-2)
Injector (I8-2) - #30 (E3-3)
Injector (I9-2) - #40 (E3-4)

Standard (Check for short):

TESTER CONNECTION AND SPECIFIED CONDITION

Tester Connection	Specified Condition
Injector (I6-2) or #10 (E3-1) - Body ground	10 kΩ or higher
Injector (I7-2) or #20 (E3-2) - Body ground
Injector (I8-2) or #30 (E3-3) - Body ground
Injector (I9-2) or #40 (E3-4) - Body ground

Fig 8: Identifying E3 ECM Connector Terminals

Reconnect the ECM connector.
Reconnect the injector connector.

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

Disconnect the I6, I7, I8 or I9 injector connector.
Disconnect the I10 ignition switch connector.

Measure the resistance between the wire harness side connectors.

Standard (Check for open):

TESTER CONNECTION AND SPECIFIED CONDITION

Tester Connection	Specified Condition
Injector (I6-1)-IG2 (I10-6)	Below 1Ω
Injector (I7-1)-IG2 (I10-6)
Injector (I8-1)-IG2 (I10-6)
Injector (I9-1)-IG2 (I10-6)

Fig 9: Identifying Ignition Switch Connector Terminals

Standard (Check for short):

TESTER CONNECTION AND SPECIFIED CONDITION

Tester Connection	Specified Condition
Injector (I6-1) or IG2 (I10-6)-Body ground	10 kΩ or higher
Injector (I7-1) or IG2 (I10-6)-Body ground
Injector (I8-1) or IG2 (I10-6)-Body ground
Injector (I9-1) or IG2 (I10-6)-Body ground

Reconnect the ignition switch connector.
Reconnect the injector connector.

NG : REPAIR OR REPLACE HARNESS OR CONNECTOR
OK : GO TO NEXT STEP

: INSPECT FUEL INJECTOR INJECTION AND VOLUME OF MISFIRING CYLINDER (See INSPECTION )
- NG : REPLACE FUEL INJECTOR ASSY
- OK : GO TO NEXT STEP
CHECK CYLINDER COMPRESSION PRESSURE OF MISFIRING CYLINDER (See ENGINE ASSEMBLY )
- NG : REPAIR OR REPLACE
- OK : GO TO NEXT STEP
CHECK VALVE CLEARANCE OF MISFIRING CYLINDER (See VALVE CLEARANCE )
- NG : ADJUST VALVE CLEARANCE (See VALVE CLEARANCE )
- OK : GO TO NEXT STEP
: SWITCH STEP BY NUMBER OF MISFIRE CYLINDER (REFER RESULT OF STEP 4)
HINT:
- If the result of step 4 is "1 or 2 cylinders" proceed to A.
- If the result of step 4 is "more than 3 cylinders" proceed to B.
- B : CHECK FOR INTERMITTENT PROBLEMS (See CHECK FOR INTERMITTENT PROBLEMS )
- A : GO TO NEXT STEP
: CHECK VALVE TIMING (CHECK FOR LOOSENESS OR A JUMPED TOOTH OF THE TIMING CHAIN) (See REPLACEMENT )
- NG : ADJUST VALVE TIMING (See TIMING CHAIN OR BELT COVER OIL SEAL ) (REPAIR OR REPLACE TIMING CHAIN)
- OK : GO TO NEXT STEP
CHECK FUEL PRESSURE (See ON-VEHICLE INSPECTION )
- NG : CHECK AND REPLACE FUEL PUMP, PRESSURE REGULATOR, FUEL PIPE LINE AND FILTER
- OK : GO TO NEXT STEP

: READ VALUE OF HAND-HELD TESTER OR OBD II SCAN TOOL (INTAKE AIR TEMPERATURE AND MASS AIR FLOW RATE)

Connect the hand-held tester or the OBD II scan tool to the DLC3.
Turn the ignition switch ON.
Check the intake air temperature.
1. Select the item "DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / INTAKE AIR" and read its value displayed on the hand-held tester or the OBD II scan tool.
  Temperature: Equivalent to ambient temperature

Check the air flow rate.

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

Standard:

AIR FLOW RATE REFERENCE

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
From idling to quickly accelerating	Air flow rate fluctuates

NG : REPLACE MASS AIR FLOW SENSOR
OK : GO TO NEXT STEP

: INSPECT ENGINE COOLANT TEMPERATURE SENSOR (RESISTANCE)

Remove the engine coolant temperature sensor.

Measure the resistance between the terminals of the engine coolant temperature sensor.

Standard:

Fig 10: Inspecting Engine Coolant Temperature Sensor

TESTER CONNECTION AND SPECIFIED CONDITION

Tester Connection	Temperature	Specified Condition
1-2	20°C(68°F)	2.32 to 2.59 kΩ
1-2	80°C(176°F)	0.310 to 0.326 kΩ

NOTE: If you checking the engine coolant temperature sensor in 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.

NG : REPLACE ENGINE COOLANT TEMPERATURE SENSOR
OK : GO TO NEXT STEP

: SWITCH STEP BY NUMBER OF MISFIRE CYLINDER (REFER RESULT OF STEP 4)
HINT:
- If the result of step 4 is "1 or 2 cylinders" proceed to A.
- If the result of step 4 is "more than 3 cylinders" proceed to B.
- B : AGAIN GO TO STEP 5
- A : CHECK FOR INTERMITTENT PROBLEMS (See CHECK FOR INTERMITTENT PROBLEMS )