Automatic Idle Speed Motor (AIS)

The AIS is mounted on the throttle body assembly and is controlled by electrical signal from the logic module. The logic module uses sensor input to determine optimum engine idle speed for any idle condition.

The AIS is then adjusted to allow a specific amount of air through an air by-pass on the back of the throttle body. This by-pass is enlarged or restricted, as an increase or decrease in engine idle speed is required to meet varying engine operating conditions.

This results in a change in air/fuel ratio, which alters the oxygen content of the exhaust gases as detected by the oxygen sensor. The logic module then changes the amount of fuel introduced into the intake charge to maintain an ideal air/fuel ratio.