Idle Speed Control (ISC) Solenoid

An air passage by-passing the throttle valve is provided to route filtered air directly into intake manifold. The flow of air through this passage is regulated by a control unit energized ISC solenoid. Solenoid is located on side of throttle body.

Air is allowed to pass through ISC solenoid when it is energized. Solenoid is energized whenever idle speed drops to less than desired RPM due to engine load (i.e. electrical, A/C, P/S, auto. trans. in Drive, etc.). ISC solenoid is also energized each time engine is started, or during periods of deceleration (to compensate for rich mixtures caused by a fully closed throttle). Duration of ISC operation is dependent on coolant temperature.