Idle Speed/Throttle Actuator - Electronic: Description and Operation

Idle Speed Control (ISC) System:

The Idle Speed Control Valve controls idle speed by allowing additional air into the intake plenum. The ISC Valve is mounted on the front end of the intake plenum and operates as a vacuum switching valve when the ECU grounds the circuit. The ECU senses electrical loads and uses the fixed idle parameters to maintain proper idle specifications. The ISC Valve inputs the ECU through terminal V-ISC.