Voyager L4-2.4L VIN B (2001)
Idle Air Control (IAC) Motor: Description and Operation
Fig. 11 TPS/IAC
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, coolant temperature or barometric pressure
changes.
The throttle body has an air bypass passage that provides air for the engine during closed throttle idle. 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 IAC 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, MAP sensor, vehicle speed sensor and
various switch operations (brake, park/neutral, air conditioning).
When engine rpm is above idle speed, the IAC is used for the following functions:
-
Off-idle dashpot
-
Deceleration air flow control
-
A/C compressor load control (also opens the passage slightly before the compressor is engaged so that the engine rpm does not dip down when the
compressor engages)
Target Idle
Target idle is determined by the following inputs:
-
Gear position
-
ECT Sensor
-
Battery voltage
-
Ambient/Battery Temperature Sensor
-
VSS
-
TPS
-
MAP Sensor
