Grand Caravan FWD V6-3.0L VIN 3 (1999)
Idle Speed/Throttle Actuator - Electronic: Description and Operation
IDLE AIR CONTROL MOTOR-PCM OUTPUT
The idle air control motor is mounted on the throttle body. The PCM operates the idle air control motor. The PCM adjusts engine idle speed
through the idle air control motor to compensate for engine load or ambient conditions.
The throttle body has an air bypass passage that provides air for the engine at idle (the throttle blade is closed). The idle air control motor pintle
protrudes into the air bypass passage 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 bypass passage. The adjustments are based on
inputs the PCM receives. The inputs are from the throttle position sensor, crankshaft position sensor, coolant temperature sensor, and various
switch operations (brake, park/neutral, air conditioning). Deceleration die out is also prevented by increasing airflow when the throttle is closed
quickly after a driving (speed) condition.
