Tracker 4WD V6-2.5L VIN 4 (2001)
Idle Air Control Motor (IAC): Testing and Inspection
IDLE AIR CONTROL (IAC) SYSTEM DIAGNOSIS
CIRCUIT DESCRIPTION
The Powertrain Control Module (PCM) controls the Idle Air Control (IAC) valve in order to regulate the air flow through the idle air bypass passage.
The amount of air flowing through the idle air bypass passage determines the idle speed. The PCM directs the IAC valve according to changes in
engine load. A stalling or poor idle concern could be caused by an IAC valve that is not operating properly.
DIAGNOSTIC AIDS
Any condition that can affect engine performance at idle, can affect the performance of the IAC system. A careful visual and/or physical inspection of
the engine is necessary when the scan tool indicates that the engine speed or the IAC Motor Command readings are out of range.
A warm engine that is idling too slow, with a high IAC Motor Command of 50 percent or more, may have an open in the ignition positive voltage
circuit to terminal 5.
A warm engine that is idling too fast, with a low IAC Motor Command of 15 percent or less, may have an open in the ignition positive voltage circuit
to terminal 2.
An intermittent IAC system concern may be caused by poor electrical connections in the IAC valve circuits. Thoroughly check any circuitry that is
suspected of causing an intermittent condition. Refer to Intermittent Conditions. See: Computers and Control Systems/Testing and Inspection/Initial
Inspection and Diagnostic Overview/Diagnostic Strategies/Intermittent Conditions
IAC Valve Terminal (Pin) Location
Use the above table in order to locate the correct terminals to test during diagnosis. The table layout corresponds to the pin location of the IAC valve
electrical terminals.
TEST DESCRIPTION