Inspection Procedure

WARNING: This page is about a different variant/trim than selected.

HINT:

If DTCs besides misfire DTCs are memorized simultaneously, troubleshoot the non-misfire DTCs first. Read freeze frame data using the hand-held tester or the OBDII scan tool. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, 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 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, cylinder specific misfire fault codes are disabled at high engine speeds. If the misfire starts in a high engine speed area or the misfire occurs only in a high engine speed area, only the general fault code P0300 will be stored.
When only a general misfire fault code like P0300 is stored:
1. Erase the general misfire fault code from the ECM using the hand-held tester or OBD II scan tool.
2. Start the engine and drive the confirmation pattern.
3. Read the value of the misfire ratio for each cylinder. Or read the DTC.
4. Perform repairs on the cylinder that has a high misfire ratio. Or repair the cylinder indicated by the DTC.
5. After finishing repairs, drive the confirmation pattern again and confirm that no misfire occurs.
When either of SHORT FT #1, LONG FT #1 in the freeze frame data is over the range of +/-20 %, there is a possibility that the air-fuel ratio is becoming too 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.

CHECK OTHER PTC OUTPUT (IN ADDITION TO MISFIRE DTCS)

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

Result:

DTC RESULT

Display (DTC Output)	Proceed to
Only P0300, P0301, P0302, P0303, P0304 are output	A
P0300, P0301, P0302, P0303, P0304 and other DTCs are output	B

HINT:

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

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
1. Check the connection conditions of the wire harness and connector.
2. Check for the disconnection, piping and break of the vacuum hose.
  OK: Connected correctly and no damage on wire harness.
1. NG: REPAIR OR REPLACE, THEN CONFIRM THAT THERE IS NO MISFIRE
2. OK: GO TO NEXT STEP.
CHECK CONNECTION OF PCV HOSE
OK: PCV hose is connected correctly and PCV hose has no damage.
1. NG: REPAIR OR REPLACE PCV HOSE
2. 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 ON the ignition switch. Push the hand-held tester or the OBD II scan tool main switch ON.
Start the engine.
Enter the following menus: DIAGNOSIS/ENHANCED OBD II/DATA LIST/ALL/CYL#1 to CYL#4.
Read the number of misfires on the hand-held tester or the OBD II scan tool.

HINT:

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

Result:

DTC RESULT

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.
Remove the spark plug.

Check the spark plug type.

Recommended spark plug:

SPARK PLUG SPECIFICATIONS

DENSO made	SK20R11
NGK made	IFR6A11

Measure the spark plug electrode gap.
Standard: 1.0 to 1.1 mm (0.039 to 0.043 in.)

Maximum: 1.3 mm (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: Always disconnect each injector connector.

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

Install the spark plug to the ignition coil and connect the ignition coil connector.
Disconnect the injector connector.
Ground the spark plug.
Check if spark occurs while the engine is being cranked.

Fig 1: Checking For Spark

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Spark jumps across electrode gap.

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

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

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 spark occurs while the engine is being cranked.
OK: Spark jumps across electrode gap.
1. OK: REPLACE SPARK PLUG
2. NG: GO TO NEXT STEP.
CHECK WIRE HARNESS OF MISFIRING CYLINDER (IGNITION COIL - ECM)
1. Check the wire harness between the ignition coil and ECM.
  1. Disconnect the I2, I3, I4 and I5 ignition coil connectors.
  2. Disconnect the E7 ECM connector.
  3. Measure the resistance of the wire harness side connectors.
    Standard:
    
    Fig 2: Testing Resistance At Wiring Harness Side Connectors
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  4. Disconnect the I2, I3, I4 and I5 ignition coil connectors.
2. Check the wire harness between the ignition coil and ECM.
  1. Disconnect the I2, I3, I4 and I5 ignition coil connectors.
  2. Disconnect the E7 ECM connector.
  3. Measure the resistance of the wire harness side connectors.
    
    Fig 4: Testing Resistance At Wiring Harness Side Connectors
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    
    Fig 5: Identifying Ignition Coil & ECM Connector Terminals
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    
    Standard:
1. OK: REPLACE IGNITION COIL ASSY (THEN CONFIRM THAT THERE IS NO MISFIRE)
2. NG: REPAIR OR REPLACE HARNESS AND CONNECTOR

INSPECT ECM TERMINAL OF MISFIRING CYLINDER (#1, #2, #3, #4 VOLTAGE)

Turn the ignition switch ON.

Measure the voltage of the ECM connectors.

Fig 6: Identifying ECM Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Standard:

Fig 7: Testing Voltage At ECM Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:

Reference: Inspection using an oscilloscope. Check the waveform of the ECM connectors.

Standard:

TESTER CONNECTION AND CONDITION SPECIFICATIONS

Tester Connection	Condition	Specified Condition
#1 to #4 - E01	Engine idling	Connect waveform is as shown

Fig 8: Checking Waveform At ECM Connector

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 )
1. NG: REPLACE FUEL INJECTOR ASSY (See appropriate Fuel Systems article)
2. OK: GO TO NEXT STEP.
CHECK WIRE HARNESS OF MISFIRING CYLINDER (INJECTOR - ECM, INJECTOR - IGNITION SWITCH)
1. Check the wire harness between the injector and ECM.
  1. Disconnect the I8, I9, I10 and I11 injector connectors.
  2. Disconnect the E7 ECM connector.
  3. Measure the resistance of the wire harness side connectors.
    
    Fig 9: Identifying Injector & ECM Connector Terminals
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  Standard:
  
  Fig 10: Resistance Test Specifications
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Check the IG2 fuse.
  1. Remove the IG2 fuse from the instrument panel J/B.
  2. Measure the resistance of the IG2 fuse.
    
    Fig 11: Locating IG2 Fuse
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    
    Standard: Below 1 Ω.
3. Check the wire harness between the injector and ignition switch.
  1. Disconnect the I8, I9, I10 and I11 injector connectors.
  2. Disconnect the I15 ignition switch connector.
  3. Measure the resistance of the wire harness side connectors.
    
    Fig 12: Identifying Injectorr & Ignition Switch Connector Terminals
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    
    Standard:
    
    Fig 13: Resistance Test Specifications
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: REPAIR OR REPLACE HARNESS AND CONNECTOR
2. OK: GO TO NEXT STEP.

INSPECT FUEL INJECTOR INJECTION AND VOLUME OF MISFIRING CYLINDER (See INSPECTION )

Standard:

FUEL INJECTOR INJECTION VOLUME SPECIFICATIONS

Injection Volume	Difference Between Each Injector
76 to 91 cm³ (4.6 to 5.5 cu in.) /15 seconds	15 cm³ (0.9 cu in.) or less

NG: REPLACE FUEL INJECTOR ASSY
OK: GO TO NEXT STEP.

CHECK CYLINDER COMPRESSION PRESSURE OF MISFIRING CYLINDER

See INSPECTION

Standard:

MISFIRING CYLINDER COMPRESSION PRESSURE CONDITION SPECIFICATIONS

Item	Specified Condition
Compression pressure	1.360 MPa (13.9 kgf/cm² , 198 psi)
Minimum pressure	0.98 MPa (10 kgf/cm² , 142 psi)
Difference between each cylinder	0.1 MPa (1.0 kgf/cm² , 14 psi)

NG: REPAIR OR REPLACE
OK: GO TO NEXT STEP.

CHECK VALVE CLEARANCE OF MISFIRING CYLINDER (See ADJUSTMENT )

Standard (cold):

MISFIRING CYLINDER VALVE CLEARANCE CONDITION SPECIFICATIONS

Item	Specified Condition
Intake	0.19 to 0.29 mm (0.0075 to 0.0114 in.)
Exhaust	0.30 to 0.40 mm (0.0118 to 0.0157 in.)

NG: ADJUST VALVE CLEARANCE (See ADJUSTMENT )
OK: GO TO NEXT STEP.

SWITCH STEP BY NUMBER OF MISFIRE CYLINDER (REFER TO RESULTS 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.
1. B: CHECK FOR INTERMITTENT PROBLEMS (See CHECK FOR INTERMITTENT PROBLEMS )
2. A: GO TO NEXT STEP.
CHECK VALVE TIMING (See REPLACEMENT )
1. Check for loose or jumped tooth of the timing chain.
  OK: The matchmarks of the crankshaft pulley and camshaft pulley are alined.
1. NG: ADJUST VALVE TIMING (See REPLACEMENT )
2. OK: GO TO NEXT STEP.

CHECK FUEL PRESSURE (See ON-VEHICLE INSPECTION )

Standard:

FUEL PRESSURE CONDITION SPECIFICATIONS

Item	Specified Condition
Fuel pressure	304 to 343 kPa (3.1 to 3.5 kgf/cm² , 44 to 55 psi)

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. On the hand-held tester or the OBD II scan tool, enter the following menus: DIAGNOSIS/ENHANCED OBD II/DATA LIST/ALL/INTAKE AIR. Read the values.
  Temperature: Equivalent to ambient temperature

Check the air flow rate.

On the hand-held tester or the OBD II scan tool, enter the following menus: DIAGNOSIS/ENHANCED OBD II/DATA LIST/ALL/MAR Read the values.

Standard:

AIR FLOW RATE SPECIFICATIONS

Condition	Air Flow Rate (gm/s)
Ignition switch ON (do not start engine)	0
Idling	0.5 to 5
Running without load (2,500 rpm)	3 to 10
Idling to quickly accelerating	Air flow rate fluctuates

NG: REPLACE MASS AIR FLOW METER
OK: GO TO NEXT STEP.

INSPECT ENGINE COOLANT TEMPERATURE SENSOR (RESISTANCE)

Remove the ECT sensor.

Measure the resistance between the terminals.

Fig 14: Measuring Resistance Between Terminals

Standard:

TESTER CONNECTION AND CONDITION SPECIFICATIONS

Tester Connection	Condition	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 checking the ECT sensor in water, be careful not to allow water to contact the terminals. After the check, dry the sensor.

HINT:

Alternate procedure: Connect an ohmmeter to the installed ECT 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 TO RESULTS 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.
1. B: AGAIN GO TO STEP 5
2. A: GO TO NEXT STEP.
3. CHECK FOR INTERMITTENT PROBLEMS (See CHECK FOR INTERMITTENT PROBLEMS )