Toyota Repair: Rav4 error code P0505, going in the right direction, idle control system malfunction

Question
A couple of months ago I was at a lube shop and recommended that I get a fuel system cleaning on my 1998 rav4 2door auto with air.They hooked my car up to some gadget with air and a liquid that went into the throttle body and added something to the gas.I was left with the car to keep the revs up and the tech told me if the engine light goes on then tell him.It didnt at that time but three weeks later it did go on sometimes and now all the time.I purchased a code reader and it came up P0505 wich as you would know is the Idle control system malfunction.
I went through other E mails that you answered to a number of people and I am leaning towardes testing the IAC valve resistance and/or inspecting the operation of the valve with a 12v battery.Do you think I am going in the right direction?...Thankyou very much..Ron in Ontario Canada

Answer
You can save some time by just replacing the ISC valve, or if you want to try cleaning it remove the throttle body and remove the valve from the throttle body then clean the carbon deposits out of the valve and clean the throttle body inside also, reassemble everything  and clear the code.