Inspection Procedure

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, 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. 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.
• When one of SHORT FT #1, LONG FT #1, SHORT FT #2 and LONG FT #2 in the freeze frame data is outside 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.

1. CHECK OTHER DTC OUTPUT (IN ADDITION TO MISFIRE DTCS) 
   1. Connect the hand-held tester or the OBD II scan tool to the DLC3.
   2. Turn the ignition switch to ON and turn the hand-held tester or the OBD II scan tool ON.
   3. Select the item: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
   4. Read DTCs.

      Result: 

      Fig 1: DTC Output Result Table

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   HINT: If any other codes besides P0300, P0301, P0302, P0303, P0304, P0305 or P0306 are output, perform troubleshooting for those DTCs first.

   B: GO TO RELEVANT DTC CHART (See  DIAGNOSTIC TROUBLE CODE CHART  ) 

   A: GO TO NEXT STEP. 

2. CHECK WIRE HARNESS, CONNECTOR AND VACUUM HOSE IN ENGINE ROOM 
   1. Check the connection conditions of the wire harness and connector.
   2. Check the piping of the vacuum hose.
   3. Check the vacuum hose for disconnection or breakage.

   NG: REPAIR OR REPLACE, THEN CONFIRM THAT THERE IS NO MISFIRE 

   OK: GO TO NEXT STEP. 

3. CHECK CONNECTION OF PCV HOSE 

   NG: REPAIR OR REPLACE PCV HOSE 

   OK: GO TO NEXT STEP. 

4. READ VALUE OF HAND-HELD TESTER OR OBD II SCAN TOOL (NUMBER OF MISFIRE) 
   1. Connect the hand-held tester or the OBD II scan tool to the DLC3.
   2. Turn the ignition switch to ON and turn the hand-held tester or the OBD II scan tool ON.
   3. Start the engine.
   4. Select the item: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / CYL#1 to CYL#6.
   5. 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: 

   Fig 2: Hand-Held Tester Result Table (High Misfire Rate Cylinder)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   B: Go to step   15 

   A: GO TO NEXT STEP. 

5. CHECK SPARK PLUG AND SPARK OF MISFIRING CYLINDER 
   1. Remove the ignition coil assembly.
   2. Remove the spark plug.
   3. Check the spark plug type.

      Recommended spark plug: 

      Fig 3: Recommended Spark Plug Table

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      Fig 4: Removing Spark Plug And Identifying Electrode Gap

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   4. Check the spark plug electrode gap.

      Electrode gap: 1.0 to 1.1 mm (0.039 to 0.043 in.) 

      Maximum electrode gap: 1.3 mm (0.051 in.) 

      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.
   5. Check the electrode for carbon deposits.
   6. Perform a spark test.
      CAUTION: Absolutely disconnect the each injector connectors.
      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.

         Standard: Spark jumps across electrode gap. 

   7. Reinstall the spark plug.
   8. Reinstall the ignition coil assy.

   OK: Go to step   8 

   NG: GO TO NEXT STEP. 

6. 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 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.

         Standard: Spark jumps across electrode gap. 

   OK: REPLACE SPARK PLUG 

   NG: GO TO NEXT STEP. 

7. CHECK HARNESS AND CONNECTOR OF MISFIRING CYLINDER (IGNITION COIL - ECM) 
   1. Check the harness and connector between the ignition coil and the ECM (IGF1 terminal) connectors
      1. Disconnect the I1, I2, I3, I4, I5 or I6 ignition coil connector.
      2. Disconnect the E10 ECM connector.
      3. Check the resistance between the wire harness side connectors.

         Standard (Check for open): 

         Fig 5: Ignition Coil And ECM Terminals Specified Condition Chart (Check For Open)

         Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

         Standard (Check for short): 

         Fig 6: Ignition Coil And ECM Terminals Specified Condition Chart (Check For Short)

         Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      4. Reconnect the ignition coil connector.
      5. Reconnect the ECM connector.
         Fig 7: Identifying Ignition Coil Connector

         Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
         Fig 8: Disconnecting E10 ECM Connector

         Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   2. Check the harness and the connector between the ignition coil and the ECM (IGT terminal) connectors
      1. Disconnect the I1, I2, I3, I4, I5 or I6 ignition coil connector.
      2. Disconnect the E10 ECM connector.
      3. Check the resistance between the wire harness side connectors.

         Standard (Check for open): 

         Fig 9: Ignition Coil And ECM Terminals Specified Condition Chart (Check For Open)

         Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

         Standard (Check for short): 

         Fig 10: Ignition Coil And ECM Terminals Specified Condition Chart (Check For Short)

         Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      4. Reconnect the ignition coil connector.
      5. Reconnect the ECM connector.
         Fig 11: Identifying Ignition Coil Connector

         Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
         Fig 12: Connecting E10 ECM Connector

         Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK: REPLACE IGNITION COIL ASSY (THEN CONFIRM THAT THERE IS NO MISFIRE) 

   NG: GO TO NEXT STEP. 

   REPAIR OR REPLACE HARNESS OR CONNECTOR 

8. INSPECT ECM TERMINAL OF MISFIRING CYLINDER(#10, #20, #30, #40, #50 OR #60 VOLTAGE) 
   1. Turn the ignition switch ON.
   2. Measure the voltage between the applicable terminals of the E9 and E10 ECM connectors.

      Standard: 

      Fig 13: Misfiring Cylinder ECM Terminals Specified Condition Chart

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      Fig 14: Identifying Misfiring Cylinder ECM Connector Terminals

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK: Go to step   9 

   NG: GO TO NEXT STEP. 

9. INSPECT FUEL INJECTOR RESISTANCE OF MISFIRING CYLINDER (See  INSPECTION  ) 

   NG: REPLACE FUEL INJECTOR ASSY (See  FUEL INJECTOR ASSY (3MZ-FE)  ) 

   OK: GO TO NEXT STEP. 

10. CHECK HARNESS AND CONNECTOR OF MISFIRING CYLINDER (INJECTOR - ECM, INJECTOR - IGNITION SWITCH) 
    1. Check the harness and the connector between the injector connector and the ECM connector.
       1. Disconnect the I7, I8, I9, I10, I11 or I12 injector connector.
       2. Disconnect the E9 or E10 ECM connector.
       3. Check the resistance between the wire harness side connectors.

          Standard (Check for open): 

          Fig 15: Injector Terminals And Ignition Switch Terminals Specified Condition Chart (Check For Open)

          Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

          Standard (Check for short): 

          Fig 16: Injector Terminals And Ignition Switch Terminals Specified Condition Chart (Check For Short)

          Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
       4. Reconnect the injector connector.
       5. Reconnect the ECM connector.
          Fig 17: Identifying Injector Connector

          Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
          Fig 18: Disconnecting E9 Or E10 ECM Connector

          Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
          Fig 19: Identifying IGN Fuse

          Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
          Fig 20: Identifying Ignition Switch Connectors

          Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Check the harness and the connector between the injector connector and the ignition switch connector.
       1. Inspect the IGN fuse.
          • Remove the IGN fuse from the engine room J/B.
          • Check for continuity in the IGN fuse.

            Standard: Continuity 

          • Reinstall the IGN fuse.
       2. Disconnect the I7, I8, I9, I10, I11 or I12 injector connector.
       3. Disconnect the I14 ignition switch connector.
       4. Check the resistance between the wire harness side connectors.

          Standard (Check for open): 

          Fig 21: Injector Connector Terminals Specified Condition Chart (Check For Open)

          Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

          Standard (Check for short): 

          Fig 22: Injector Connector Terminals Specified Condition Chart (Check For Short)

          Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
       5. Reconnect the injector connector.
       6. Reconnect the ignition switch connector.

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: GO TO NEXT STEP. 

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

    NG: REPLACE FUEL INJECTOR ASSY 

    OK: GO TO NEXT STEP. 

12. CHECK CYLINDER COMPRESSION PRESSURE OF MISFIRING CYLINDER (See  INSPECTION  ) 

    NG: REPAIR OR REPLACE 

    OK: GO TO NEXT STEP. 

13. CHECK VALVE CLEARANCE OF MISFIRING CYLINDER (See  VALVE CLEARANCE (3MZ-FE)  ) 

    NG: ADJUST VALVE CLEARANCE (See  VALVE CLEARANCE (3MZ-FE)  ) 

    OK: GO TO NEXT STEP. 

14. 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. 

15. CHECK VALVE TIMING (CHECK FOR LOOSENESS OR A JUMPED TOOTH OF THE TIMING BELT) (See  TIMING BELT (3MZ-FE)  ) 

    NG: ADJUST VALVE TIMING (See  TIMING BELT (3MZ-FE)  ) (REPAIR OR REPLACE TIMING BELT) 

    OK: GO TO NEXT STEP. 

16. 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. 

17. READ VALUE OF HAND-HELD TESTER OR OBD II SCAN TOOL (INTAKE AIR TEMPERATURE AND MASS AIR FLOW RATE) 
    1. Connect the hand-held tester or the OBD II scan tool to the DLC3.
    2. Turn the ignition switch to ON and turn the hand-held tester or the OBD II scan tool ON.
    3. Check the intake air temperature.
       1. On the hand-held tester or the OBD II scan tool, select the item: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / INTAKE AIR. Read the values.

          Temperature: Equivalent to ambient air temperature 

    4. Check the air flow rate.
       1. On the hand-held tester or the OBD II scan tool, select the item: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / MAF. Read the values.

          Standard: 

          Fig 23: Engine Condition And Air Flow Rate Table

          Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE MASS AIR FLOW METER 

    OK: GO TO NEXT STEP. 

18. INSPECT ENGINE COOLANT TEMPERATURE SENSOR (RESISTANCE) 
    1. Remove the engine coolant temperature sensor.
    2. Measure the resistance between the terminals.

       Standard: 

       Fig 24: Engine Coolant Temperature Sensor Terminals Specified Condition Chart

       Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
       Fig 25: Measuring Resistance Between Engine Coolant Temperature Sensor Terminals

       Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
       NOTE: When checking the engine coolant temperature 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 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.

    3. Reinstall the engine coolant temperature sensor.

    NG: REPLACE ENGINE COOLANT TEMPERATURE SENSOR 

    OK: GO TO NEXT STEP. 

19. 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: GO TO NEXT STEP. 

    CHECK FOR INTERMITTENT PROBLEMS (See  CHECK FOR INTERMITTENT PROBLEMS  )