Idle Air Control Valve

Idle Air Control Valve:

When the accelerator is released, the throttle is fully closed and the only air supplied to the engine is admitted via the idle air control (IAC) valve, which is opened and closed by signals from the ECM. The ECM will hold the idle speed at 850 rpm when an activating signal is received from:

^ A/C or ACC

The ECM is programmed to increase engine rpm when signals are received from:

^ DRIVE


Cars with TCS
On cars with TCS, the ETS control module takes over control of idling speed. Because of the electronic throttle housing on these cars, no IAC valve is necessary.

The ETS control module sends throttle position signals to the ECM.