Avalon 1995-1996

Idle Air Control Valve

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Location



Specific to:

Toyota Avalon 1995-1996



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Fig. Idle Air Control (IAC) Valve location

Operation



Specific to:

Toyota Avalon 1995-1996

The ECM is programmed with specific engine speed values to respond to different engine conditions (coolant temperature, air conditioner on/off, etc.). Sensors transmit signals to the ECM which controls the flow of air through the bypass of the throttle valve and adjusts the idle speed to the specified value. Some vehicles use an Idle Speed Control (ISC) valve while others use an Air Valve (AV) or Idle Air Control (IAC) valve to control throttle body by-pass air flow.

Removal & Installation



Specific to:

Toyota Avalon 1995-1996

  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Remove the throttle body from the vehicle.
  4.  
  5. Remove the four screws that attach the Idle Air Control (IAC) valve to the throttle body.
  6.  
  7. Lift the ISC valve from the throttle body and remove the gasket. Discard the gasket.

    Click image to see an enlarged view

    Fig. The idle air control valve secured to the bottom of the throttle body with four screws



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    Fig. Be sure to discard the old IAC gasket once the throttle body and valve are separated

  8.  

To install:

  1. Place the new gasket onto the throttle body.
  2.  
  3. Install the ISC valve onto the throttle body and install the four screws.
  4.  
  5. Install the throttle body into the vehicle.
  6.  
  7. Inspect the throttle linkage for freedom of movement.
  8.  

Testing



Specific to:

Toyota Avalon 1995-1996


NOTE
The idle speed must be set correctly before testing the valve. Make sure the A/C is off during testing.



Click image to see an enlarged view

Fig. The IAC valve is attached to the lower portion of the throttle body

  1. Bring the engine to normal operating temperature with transmission in N.
  2.  
  3. Using a jumper wire, connect the terminals TE1 and El of the check connector (DLC 1).
  4.  
  5. The engine rpm should rise to 1000 rpms for 5 seconds. Check that it returns to idle speed. If rpm is as specified, the valve is functioning properly.
  6.  
  7. If rpm did not function as specified, stop the engine and disconnect the jumper wire.
  8.  
  9. Disengage the ISC valve connector.
  10.  
  11. Using an ohmmeter, measure the resistance between the +B terminal (middle terminal) and the RSC and RSO outer terminals.

    Click image to see an enlarged view

    Fig. Attach an ohmmeter and measure the resistance between the three terminals

  12.  
  13. The resistance should be 21-28.5 ohms on a hot engine.
  14.  
  15. If not as specified, replace the ISC valve.
  16.  

 
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