Idle Speed/Throttle Actuator - Electronic: Description and Operation

Idle Air Control (IAC) Valve:

PURPOSE
The IAC is used to provide a cold fast idle as well as a stable idle under normal operating conditions.

LOCATION
The idle air control valve (IAC) is mounted on the intake manifold.

CONSTRUCTION
Is a linear solenoid valve, with adjustable air passages.

OPERATION
The IAC is powered by ignition switch terminal Ign. 1 and receives power anytime the ignition is turned ON. The ECM controls the ground circuit. The valve is used to correct idle speed when out of normal operating parameters. Idle speed is modified by allowing air to bypass the throttle plate. By varying the current of the signal to the IAC the ECM is able to control the position of the IAC plunger.