The Idle Speed Control (ISC) actuator has two coils that are driven by separate ECM driver stages. Depending on the pulse duty factor, the equilibrium of the magnetic forces of the two coils will result in different directions for the magnetic forces of the two coils which will result in different positions for the actuator. In parallel to the throttle valve, a bypass hose line is arranged where the ISC actuator is inserted.

The ECM will set a code and the MIL will turn on if ISC actuator's opening coil driver stage [for P1505] or closing coil driver stage [for P1507] is open or shorted to ground during two driving cycles.