ES300 1992-1997

Idle Air Control Valve

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Location



Specific to:

Lexus ES300 1993-1999



Click image to see an enlarged view

Fig. Idle Air Control (IAC) Valve-1996 models shown, other models similar

Removal & Installation



Specific to:

Lexus ES300 1993-1999

  1. Disconnect the negative battery cable.
  2.  
  3. Remove throttle body.
  4.  
  5. Remove the screws/bolts, bracket (as applicable), IAC valve and gasket.

    Click image to see an enlarged view

    Fig. Remove the bolts, IAC valve and gasket-1993 models



    Click image to see an enlarged view

    Fig. Remove the screws, IAC valve and gasket-1994-98 models



    Click image to see an enlarged view

    Fig. Remove the screws, bracket, IAC valve and gasket-1999 models

  6.  

To install:

  1. Installation is the reverse of removal. Place a new gasket on the throttle body.
  2.  

Testing



Specific to:

Lexus ES300 1993

  1. Check the IAC valve operating sound:
    1. Check that there is a clicking sound immediately stopping the engine.
    2.  

  2.  
  3. Inspect the IAC valve resistance:
    1. Disconnect the IAC valve connector.
    2.  
    3. Using an ohmmeter, measure the resistance between terminals B1-S1 or S3, and B2-S2 or S4. Resistance:

      B1-S1 or S3: 10-30 Ohms
       
      B2-S2 or S4: 10-30 Ohms
       

    4.  
    5. If resistance is not as specified, replace the IAC valve.
    6.  
    7. Reconnect the IAC valve connector.

      Click image to see an enlarged view

      Fig. Inspect the IAC valve resistance

    8.  

  4.  

Specific to:

Lexus ES300 1994-1999

  1. Inspect the IAC valve operation:
    1. Initial conditions:

      Engine at normal operating temperature
       
      Idle speed checked correctly
       
      Transmission in neutral position
       
      A/C switch OFF
       

    2.  
    3. Using SST (SST 09843-18020), connect terminals TE1 and E1 of the DLC1.
    4.  
    5. After engine speed is kept at approx. 1,000 rpm for 5 seconds, check that it returns to idle speed. If the engine speed operation is not as specified, check the IAC valve, wiring and ECM.
    6.  
    7. Remove the SST from the DLC1.
      NOTE
      -Cold- and -Hot- in the following sentences express the temperature of the coils themselves. -Cold- is from 14°F (-10°C) to 122°F (50°C) and -Hot- is from 122°F (50°C) to 212°F (100°C).



      Click image to see an enlarged view

      Fig. Inspect the IAC valve operation-1998 models, others similar

    8.  

  2.  
  3. Inspect the IAC valve resistance:
    1. Disconnect the IAC valve connector.
    2.  
    3. Using an ohmmeter, measure the resistance between terminal +B and other terminals (RSC, RSO). Resistance:

      Cold: 17.0-24.5 Ohms
       
      Hot: 21.5-28.5 Ohms
       
      At 68°F (20°C): 19.3-22.3 Ohms
       

    4.  
    5. If resistance is not as specified, replace the IAC valve.
    6.  
    7. Reconnect the IAC valve connector.

      Click image to see an enlarged view

      Fig. Inspect the IAC valve resistance-1998 models, others similar

    8.  

  4.  

 
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