Idle Speed/Throttle Actuator - Electronic: Description and Operation

Bypass Air Control Valve:

PURPOSE
Controls engine idle speed.

LOCATION
On the throttle chamber.

OPERATION
The bypass air control valve is regulated by a signal from the ECU. It is in an air passage bypassing the throttle valve and is utilized to control idle air intake volume and thus idle speed. The ECU calculates factors such as engine temperature, load and altitude when making idle speed adjustments.