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Home >> Lexus >> 2004 >> IS 300 Base, Standard >> Repair and Diagnosis >> Engine Performance >> Fuel Delivery >> SFI >> Throttle Body >> On-Vehicle Inspection

On-Vehicle Inspection

  1. REMOVE ENGINE COVER 

    Remove the 4 nuts and engine cover.

  2. INSPECT SYSTEM OPERATION 
    1. Check that the throttle linkage moves smoothly.
      Fig 1: Checking Movement Of Throttle Linkage
      G00893928Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Inspect the throttle control motor for operating sound.
      1. Turn the ignition switch ON.
      2. When turning the accelerator pedal position sensor lever, check the running sound of the motor. Also, check that there is no friction sound.

      If operation is not as specified, check the throttle control motor, wiring and ECM.

      Fig 2: Inspecting Throttle Control Motor Operating Sound
      G00893929Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Inspect the throttle position sensor and accelerator pedal position sensor function.
      1. Connect the hand-held tester to the DLC3.
      2. Fig 3: Connecting Hand-Held Tester To DLC3
        G00893930Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      3. When turning the accelerator pedal position sensor lever to the full-open position, check that the throttle valve opening percentage (THROTTLE POS) of the CURRENT DATA shows the standard value.

      Throttle valve opening percentage: 60% or more 

      If operation is not as specified, check that the throttle position sensor, accelerator pedal position sensor, wiring and ECM.

    4. Start the engine, and check that the Malfunction Indicator Lamp (MIL) does not light up.
    5. Inspect the air assist system.
      1. Allow the engine to warm up to normal operating temperature.
      2. Turn the A/C switch ON and OFF, and check the idle speed.
        1. Idle speed (Transmission in neutral): 
        2. 700 +/- 50 rpm (A/C OFF) 
        3. 750 +/- 50 rpm (A/C ON) 
        NOTE: Perform inspection under condition without electrical load. 
      3. With engine idling, pinch the air assist hose and check that engine speed drops, and then returns back up to idle speed.

      If operation is not as specified, check the throttle body, wiring and ECM.

    6. After checking the above ( b) to ( e), perform the diving test and check that there is no sense of incongruity.
      Fig 4: Pinching Air Assist Hose
      G00893931Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  3. INSPECT THROTTLE CONTROL MOTOR. 
    Fig 5: Inspecting Throttle Control Motor
    G00893932Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the throttle control motor connector.
    2. Using an ohmmeter, measure the resistance between terminal 3 (CL-) and 4 (CL+).
      1. Resistance: 4.2 - 5.2Ω at 20°C (68°F) 
    3. Using an ohmmeter, measure the resistance between terminal 1 (M+) and 2 (M-).
      1. Resistance: 0.3 - 100Ω at 20°C (68°F) 

      If the resistance is not as specified, replace the throttle control motor (See REPLACEMENT ).

    4. Reconnect the throttle control motor connector.
  4. INSPECT THROTTLE POSITION SENSOR 
    Fig 6: Inspecting Throttle Position Sensor
    G00893933Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the throttle position sensor connector.
    2. Using an ohmmeter, measure the resistance between terminals VC and E2.
      1. Resistance: 1.2 - 3.2Ω at 20°C (68°F) 

      If the resistance is not as specified, replace the throttle position sensor (See REPLACEMENT ).

    3. Reconnect the throttle position sensor connector.
  5. INSPECT ACCELERATOR PEDAL POSITION SENSOR 
    Fig 7: Inspecting Accelerator Pedal Position Sensor
    G00893934Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the accelerator pedal position sensor connector.
    2. Using an ohmmeter, measure the resistance between terminals VC and E2.
      1. Resistance: 1.2 - 3.2Ω at 20°C (68°F) 

      If the resistance is not as specified, replace the accelerator pedal position sensor (See REPLACEMENT ).

    3. Reconnect the accelerator pedal position sensor connector.
  6. REINSTALL ENGINE COVER 

    Install the engine cover with the 4 nuts.