ISC STEPS (range of 0 to 130)

This is your Idle Speed Control servo motor on the throttle body (you know, the one that goes bad!). It is a stepper motor that opens or closes the TB plate to control the idle speed due to load changes, i.e. turning on the a/c or using the power steering, brakes etc. It opens up in steps and closes in steps to control the idle. This value is useful to tell if the ISC is working well or not.