Auxiliary Air Valve (Idle Speed): Description and Operation

Idle Air Control Valve-Air Regulator:

PURPOSE
Provides fast idle when the engine is cold.

OPERATION
when the engine is cold, the valve is open. The valve allows intake air to by-pass the throttle valve, thereby raising engine idle speed. As the coolant temperature raises and the PTC heater (inside the valve) warms, it gradually closes off the air passage, lowering idle speed.

CONSTRUCTION
A coiled bi-metal spring is attached to a shutter valve. A PTC heater element inside the unit heats the spring, closing the shutter. In addition, the spring is heated by thermal transfer from coolant warming the thermostat housing.