Re: valvula IAC
te dejo la teoria de funcionamiento de la valvula IAC
Idle Air Control (IAC) Valve
The IAC valve controls engine idle speed to prevent stalling during engine load changes. The IAC valve is
mounted on throttle body and controls the amount of air by-passed around the throttle plate. The IAC valve
controls engine idle speed by moving its pintle in and out in steps referred to as "counts" (0 counts, fully seated;
255 counts, fully retracted). Counts can be measured by plugging a scan tester into the Data Link Connector
(DLC).
If engine RPM is too low, pintle is retracted and more air is by-passed around the throttle plate to increase
engine RPM. If engine RPM is too high, pintle is extended and less air is by-passed around the throttle plate to
decrease engine RPM. Normal counts on an idling engine should be 4-60. When engine is idling, PCM
determines proper positioning of IAC valve based on battery voltage, coolant temperature, engine load and
engine RPM.
If IAC valve is disconnected or reconnected with engine running, IAC loses its reference point and must be
reset. On some models, IAC is reset by turning ignition on and off. Other models require driving vehicle at
normal operating temperature over 35 MPH with circuit properly connected. Problems in IAC circuit should set
a related code.
The IAC valve affects only the idle system. If valve is stuck fully open, excessive airflow into the manifold
creates a high idle speed. Valve stuck closed allows insufficient airflow, resulting in low idle speed. For
calibration purposes, several different IAC valves are used. Ensure replacement valve is proper design.