2008 Lexus IS FFACTORY OEM SERVICE PROCEDURE

Inspection Procedure

  1. CHECK MIL 
    1. Check that Malfunction Indicator Lamp (MIL) illuminates when turning the engine switch on (IG).

      OK: MIL illuminates. 

    NG: Go to step 2 

    OK: SYSTEM OK 

  2. CHECK CONNECTION BETWEEN TECHSTREAM AND ECM 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG) and Techstream ON
    3. Check the communication between the Techstream and ECM

      Result 

      RESULT CHART

      Result Proceed to
      Communication is possible A
      Communication is not possible B

    A: GO TO MIL CIRCUIT 

    B: Go to next step 

  3. CHECK MIL (THROTTLE BODY) 
    1. Disconnect the throttle body connector.
    2. Turn the engine switch on (IG).
    3. Check the MIL

      Result 

      RESULT CHART

      Result Proceed to
      MIL illuminates A
      MIL does not illuminate B
    4. Reconnect the throttle body connector

    A: REPLACE THROTTLE BODY ASSEMBLY  (See REMOVAL  )

    B: Go to next step 

  4. CHECK MIL (ACCELERATOR PEDAL POSITION SENSOR) 
    1. Disconnect the accelerator pedal position sensor connector
    2. Turn the engine switch on (IG)
    3. Check the MIL.

      Result 

      RESULT CHART

      Result Proceed to
      MIL illuminates A
      MIL does not illuminate B
    4. Reconnect the accelerator pedal position sensor connector

    A: REPLACE ACCELERATOR PEDAL ASSEMBLY  (See REMOVAL  )

    B: Go to next step 

  5. CHECK MIL (CANISTER PUMP MODULE) 
    1. Disconnect the canister pump module connector
    2. Turn the engine switch on (IG)
    3. Check the MIL

      Result 

      RESULT CHART

      Result Proceed to
      MIL illuminates A
      MIL does not illuminate B
    4. Reconnect the canister pump module connector.

    A: REPLACE CANISTER ASSEMBLY  (See REMOVAL )

    B: Go to next step 

  6. CHECK MIL (CRANKSHAFT POSITION SENSOR) 
    1. Disconnect the crankshaft position sensor.
    2. Turn the engine switch on (IG).
    3. Check the MIL

      Result 

      RESULT CHART

      Result Proceed to
      MIL illuminates A
      MIL does not illuminate B
    4. Reconnect the crankshaft position sensor

    A: REPLACE CRANKSHAFT POSITION SENSOR  (See REMOVAL  )

    B: Go to next step 

  7. CHECK MIL (CAMSHAFT POSITION SENSOR) 
    1. Disconnect the camshaft position sensor
    2. Turn the engine switch on (IG).
    3. Check the MIL

      Result 

      RESULT CHART

      Result Proceed to
      MIL illuminates A
      MIL does not illuminate B
    4. Reconnect the camshaft position sensor

    A: REPLACE CAMSHAFT POSITION SENSOR  (See REMOVAL  )

    B: Go to next step 

  8. CHECK MIL (VVT SENSOR FOR INTAKE SIDE BANK 1) 
    1. Disconnect the VVT sensor for intake side bank 1 connector.
    2. Turn the engine switch on (IG)
    3. Check the MIL

      Result 

      RESULT CHART

      Result Proceed to
      MIL illuminates A
      MIL does not illuminate B
    4. Reconnect the VVT sensor for intake side bank 1 connector.

    A: REPLACE VVT SENSOR FOR INTAKE SIDE BANK 1  (See REMOVAL  )

    B: Go to next step 

  9. CHECK MIL (VVT SENSOR FOR EXHAUST SIDE BANK 1) 
    1. Disconnect the VVT sensor for exhaust side bank 1 connector.
    2. Turn the engine switch on (IG)
    3. Check the MIL

      Result 

      RESULT CHART

      Result Proceed to
      MIL illuminates A
      MIL does not illuminate B
    4. Reconnect the VVT sensor for exhaust side bank 1 connector

    A: REPLACE VVT SENSOR FOR EXHAUST SIDE BANK 1  (See REMOVAL  )

    B: Go to next step 

  10. CHECK MIL (VVT SENSOR FOR INTAKE SIDE BANK 2) 
    1. Disconnect the VVT sensor for intake side bank 2 connector
    2. Turn the engine switch on (IG)
    3. Check the MIL

      Result 

      RESULT CHART

      Result Proceed to
      MIL illuminates A
      MIL does not illuminate B
    4. Reconnect the VVT sensor for intake side bank 2 connector

    A: REPLACE VVT SENSOR FOR INTAKE SIDE BANK 2  (See REMOVAL  )

    B: Go to next step 

  11. CHECK MIL (VVT SENSOR FOR EXHAUST SIDE BANK 2) 
    1. Disconnect the VVT sensor for exhaust side bank 2 connector
    2. Turn the engine switch on (IG)
    3. Check the MIL

      Result 

      RESULT CHART

      Result Proceed to
      MIL illuminates A
      MIL does not illuminate B
    4. Reconnect the VVT sensor for exhaust side bank 2 connector

    A: REPLACE VVT SENSOR FOR EXHAUST SIDE BANK 2  (See REMOVAL  )

    B: Go to next step 

  12. CHECK MIL (FUEL PRESSURE SENSOR) 
    1. Remove the intake manifold (See REMOVAL )
    2. Disconnect the fuel pressure sensor connector
    3. Turn the engine switch on (IG).
    4. Check the MIL

      Result 

      RESULT CHART

      Result Proceed to
      MIL illuminates A
      MIL does not illuminate B
    5. Reconnect the fuel pressure sensor connector
    6. Reinstall the intake manifold (See INSTALLATION ).

    A: REPLACE FUEL PRESSURE SENSOR  (See REMOVAL )

    B: Go to next step 

  13. CHECK HARNESS AND CONNECTOR 
    1. Disconnect the throttle body connector.
    2. Disconnect the accelerator pedal position sensor connector.
    3. Disconnect the canister pump module connector
    4. Disconnect the VVT sensor for intake side (bank 1)
    5. Disconnect the VVT sensor for exhaust side (bank 1).
    6. Disconnect the VVT sensor for intake side (bank 2)
    7. Disconnect the VVT sensor for exhaust side (bank 2).
    8. Disconnect the crankshaft position sensor
    9. Disconnect the camshaft position sensor.
    10. Disconnect the fuel pressure sensor
    11. Disconnect the E3, E4 and A5 ECM connectors
    12. Measure the resistance according to the value(s) in the table below
      Fig 1: Identifying ECM Connector E3, E4 And A5
      G05751807Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance (Check for Short) 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      E4-34 (VCTA) - Body ground Always 10 kΩ or higher
      A5-23 (VCPA) - Body ground Always 10 kΩ or higher
      A5-22 (VCP2) - Body ground Always 10 kΩ or higher
      E3-18 (VC) - Body ground Always 10 kΩ or higher
    13. Reconnect the ECM connectors
    14. Reconnect the canister pump module connector
    15. Reconnect the accelerator pedal position sensor connector
    16. Reconnect the throttle body connector
    17. Reconnect the VVT sensor for intake side (bank 1)
    18. Reconnect the VVT sensor for exhaust side (bank 1).
    19. Reconnect the VVT sensor for intake side (bank 2)
    20. Reconnect the VVT sensor for exhaust side (bank 2).
    21. Reconnect the crankshaft position sensor
    22. Reconnect the camshaft position sensor.
    23. Reconnect the fuel pressure sensor

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: REPLACE ECM  (See REMOVAL  )

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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