You can erase fault codes by disconnecting the battery, but codes never say to replace parts or that they're defective. They only indicate the circuit or system that needs further diagnosis. A sensor or part referenced in a code is only the cause about half of the time. That's particularly true of idle speed motors. Two wires have to break or corrode apart inside the sealed assembly for it to set a code, and that's not likely to happen. You're more likely to find the air passage plugged with carbon, a vacuum leak, carbon on the throttle blade, a dirty mass air flow sensor, or a leak in the fresh air tube between the mass air flow sensor and throttle body. None of those things are monitored so they won't set a code. What you might get is a code related to running too lean too long, but you still have to do the diagnosis to figure out what is setting that code.
An idle speed motor can become sluggish too and not respond fast enough, which may lead to stalling when you come to a stop. That too is not monitored. The Engine Computer pulses it to set it to the desired position, but then it just assumes it went there. If idle speed is still too low, it will just keep pulsing the motor in an attempt to bring the idle speed up to where it wants it.
Monday, November 18th, 2013 AT 5:15 PM