Idle Speed Control (ISC) System

The ISC System provides start control, fast idle control, idle control and dashpot control. Start control adjusts throttle valve opening to optimum position according to engine coolant temperature.

Fast idle control is determined by position of idle switch. When idle switch is on, engine speed is controlled according to engine coolant temperature. When idle switch is off, ISC servo is actuated according to engine coolant temperature.

Idle control increases idle speed when A/C switch is turned on or when transmission is shifted from Neutral to Drive (automatic transmission only). Dashpot control delays closing of throttle valve to its normal idling position. This delay absorbs shock at the time of deceleration for better driving comfort.