Idle Air Controller/Overview 　 Idle Air Controller   Digital Linear Actuators offer incremental adjustment of airflow in the throttle bypass valve to ensure optimum idling at all times. Working in conjunction with the corresponding sensors and an electronic control unit, these devices provide a rapid response to any variation in idle speed.   The Idle Air Controller(Digital Linear actuator) allows the ECU to change engine idle speed to meet different engine conditions. It is a 4-wire stepper motor completely under ECU control and work as a controlled valve on-off rapidly under the engine management's commands to vary the air flow into the engine.