Idle Speed/Throttle Actuator - Electronic: Description and Operation

Intake Manifold Upper Section:

The Idle Air Control (IAC) Valve (# 6 in image) is located at the rear of the engine mounted to the intake manifold.

The idle air control valve regulates the volume of air that by-passes the throttle plate. By-pass air is routed through the idle air control valve and into the intake manifold.

A pulsed ground (duty cycle) from the Motronic control module regulates the opening of the idle air control valve. The duty cycle can range anywhere from 25% to 95%.

The idle air control valve is also responsible for the amount of air during starting and deceleration. The idle air control system is adaptive and no adjustments are necessary.