What should be used to clean the idle control valve? Does the valve need to be taken apart or just taken off and soaked? Is there an additive that can be used to clean it? I have P0505 DTC set on my highlander and would like to try this before spending any money on it!
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2003 Toyota Highlander Question: Idle Control Sysme Malfunction
patrick mannion from Greg Solow's Engine Room, January 19, 2009, 23:19Master
A dirty or malfunctioning Idle Control Valve (IAC) usually causes a vehicle to stall after initial cold start up, or fails to raise the engine idle speed when electrical loads or air conditioning are turned on.The idle air control motor is located at the bottom of the throttle butterfly housing. Remove the air intake ducts (with the keys out the ignition) with the air intake boot removed you will see a small diameter black plastic housing, (perhaps the diameter of a quarter) It is secured by two philips screws. Remove the two philips screws, you will see a silver colored shaft about 8mm in diameter, turn this by hand a little clockwise and counter clockwise it should move freely. Now spray some "Berrymans Chemtool" or other equivalent product down the orifice inside the throttle housing near the throttle butterfly, while gently moving the metal shaft, does it now appear to move more freely? If so you have cleaned the IAC motor. Reassemble the black plastic housing and screws. Now hold open the throttle butterfly by pulling on the throttle cable or getting an assistant to fully depress the accelerator pedal, clean the throttle butterfly area with a little "Chemtool on a piece of paper towel or using a soft tooth brush and Chemtool. Do not liberally spray Chemtool all around the throttle housing as it may damage the throttle position switch. After reassembly the vehicle may initially be difficult to start as it has excessive fuel (Chemtool) is highly flammable) you may have to depress the accelerator fully to the floor while cranking the key in the start position and releasing the accelerator pedal the moment the engine starts. If you have any doubts what so ever perhaps it is best letting a repair shop with knowledge of Toyota or Lexus products carry out this work. Many shops replace the valve but I have cleaned over 60 of them and have only replaced 2 IAC motors
Answer #2mrgrld May 11, 2010, 16:28Rookie
I've posted the answer on my Facebook Notes.
copy and paste below