Throttle Full Close Switch: Description and Operation

Idle Switch:

The Idle Switch is a vacuum operated "ON/OFF" switch connected to the intake system with a rubber hose. Because intake manifold vacuum varies with throttle position, the ECM can utilize the idle switch input signal as one of its information sources when calculating air/fuel ratio.

MAP Sensor And Idle Switch Throttle Position Diagram:

Together with the MAP sensor, the idle switch enables the ECM to discriminate between these engine conditions:

1. "Idle" is recognized when the idle switch is "ON" and MAP sensor input signal indicates less than 340 mmHg absolute.

2. "Part Throttle" is recognized when the idle switch is "OFF," regardless of MAP sensor input signal.

3. "Wide Open Throttle (WOT)" is recognized when the idle switch is "ON" and MAP sensor input signal indicates more than 340 mmHg absolute.