Idle Speed/Throttle Actuator - Electronic: Description and Operation

1997 IDLE AIR CONTROL MOTOR-PCM OUTPUT

Idle Air Control Motor:

Idle Air Passage:

The idle air control motor and housing attaches to the rear of the intake manifold plenum. The housing opens to the rear runner in the intake manifold plenum. A hose from the air cleaner plenum supplies filtered air to idle air control motor housing. The idle air control motor pintle protrudes into the housing and regulates air flow through it.

The PCM adjusts engine idle speed by moving the idle air control motor pintle in and out of the opening in the housing. The adjustments are based on inputs to the PCM. The inputs effecting idle speed include the throttle position sensor, road speed (from transmission control module), coolant temperature sensor, battery voltage and battery temperature. Also, various switch operations (brake, park(neutral, air conditioning) effect idle speed. The PCM prevents deceleration die out by increasing airflow when the throttle closes quickly.