What could cause an idle air control motor to suddenly malfunction ?
What could lead a perfectly normal, functioning idle air control motor to malfunction?
These motors are not very powerful so any built up crud can cause them to jam. Also the electrical motor windings are very thin and fragile so there may be an open winding which will keep the motor from working. I cannot discover if you can gain access to the actual winding(s) as the IAC appears to be a module with solid state drivers and switching circuitry. Of course, the correct drive signel has to get to the IAC from the ECM so check continuity. Also power comes from the system power relay and ground goes to a common point so check those two wires. That leaves the ECM to provide the correct drive signel to the IAC.
Sort of a quick answer to a general queston. Hope that helps.
The car was seated for two weeks in the mechanic shop with body work being done. Is there anyway this could have contributed?
Don’t know the car or year but a sticky throttle body from crud build up could be a problem. As long as you ran it all the time the crud was not so stiff. after sitting it might have welded together a bit.
A malfunctioning IAC is not always due to the IAC. The IAC is controlled by the CPU, but the CPU only controls it when the throttle position sensor tells the computer that your foot is off the gas. If something keeps the throttle from fully closing, such as crud in the throttle body or someone adjusting the throttle stop screw thinking that it is an idle adjustment, then the TPS will never know that your foot is off the gas.