Idle Speed Control (ISC) Valve

Idle Speed Control Valve (ISC):

The ECM receives input from various sensors and controls idle speed through the idle speed control valve. The ISC Valve provides an air bypass around the throttle valve with a dual coil electric motor that rotates a flap in the air passage. The ISC Valve has battery voltage applied to terminals B1, B2 and grounds back through the ECM via terminals ISC1, ISC2, ISC3 and ISC4. All high speed idle parameters are controlled by the ECM at start-up.