No I don't know how the ISC is susposed to act, but I know mine is for sure acting wrongly, its actually the first time I worked on the car myself, other than installing that sensor that screws into the exhaust manifold (forget its name) Hyundai dealership said that was why the maintenance light stayed on, but that was a wasted of 96 bucks and a nasty job getting the exhaust manifold tin cover bolts out without striping them.
Turned out it was just a bad battery was why the maintenance light stayed on.
I would have to look up OC to see what that is actually - hehe, I kinda teach my self as I go (Sofa College). You should be able to find out the resistance of the OC prongs and check the sensor with a 10 dollar volt ohm meter, I would think.
Just make sure you dont send the ohm meters 1.5 volts setting into any wires that might lead to the brain box or simular, less than 1 volt could destroy things. Make sure its completely unplugged from the car before testing. And the cars 12v could destroy a ohm meter in return.
Well, mine, the ISC actually hums real load and vibrates 24 hours a day with the key in off position and key out of ignition switch. Its drawing about 2 amps i would guess, cause a 650ma solar panel could not keep up. I was thinking maybe putting a 12v relay to trickingly disconect it by way of a ignition hot wire bypass, since I heard you could unplug them and the car would run fine if it was warmed up, so that would mean my tricky bypass should work where the car dont feel a thing.
I guess I'm the only one with this problem, not sure.