Idle Speed Control (ISC)

The ISC motor is an electrically driven actuator that changes the throttle stop angle by acting as a moveable idle stop. The ECU commands the ISC to control engine idle speed and maintain a smooth idle during sudden engine deceleration.

For cold engine starting, the throttle is held open for a longer period to provide adequate engine warm-up prior to normal operation. When starting a hot engine, the throttle is open for shorter time.

Under normal engine operating conditions, engine idle is maintained at a pre-programmed RPM which may vary slightly due to engine operating conditions. Under certain engine deceleration conditions, the throttle is held slightly open.