Idle Speed/Throttle Actuator - Electronic: Description and Operation

Throttle Body:

The Automatic Idle Speed (AIS) motor maintains idle speed under varying engine loads, and prevents the engine from dying when the throttle is closed suddenly during driving, by controlling air flow into the intake manifold behind the throttle plate through a bypass passage. The Single Board Engine Controller (SBEC) maintains optimum idle speed by actuating the AIS motor to open or close the bypass opening according to a programmed response to inputs from various switches and sensors.