Search for Idle air control valve :

Idle air control valve: replacement and selection

When and why idle air control valve needs replacement

The idle air control (IAC) valve has no specified lifetime limit. Replacement is performed in case of damages to the housing or to control valve connectors, as well as internal wiring breakage.

The main cause of IAC valve defect is end of its elements service life: abrasion of the lead screw, wear-out of the rod. Moreover, the idle air control valve can get damaged as a result of impact in a road accident. Also, component elements break down because of soiling (for example, if dirt gets on them).

Idle air control valve defects are indicated by unstable idle rpms and also spontaneous engine stalls at gear shifting. In many cases increased fuel consumption is noticeable.

Together with the IAC valve the seal is also replaced if the car part design includes it. Valve replacement should be performed only at a service station because you can easily break the component rod when mounting if you have no relevant experience. Moreover, on some cars you will need to calibrate the idle air control valve after its installation. It is done at a service station with a help of a computer.

How to select the idle air control valve

There are three main types of idle air control valves: solenoid, stepper motor, and rotary solenoid. Solenoid components consist of a coil and a rod which is retracted under voltage and opens the bypass air channel. In rotary solenoid valves function of the rod is performed by a rotor. It is rotating, thus changing the diameter of the bypass air channel. In the stepper motor valves the process of opening and closing of a bypass channel is performed due to a ring magnet and coils which receive impulses one by one.

Products of such manufacturers as Bosch, Hella, Magneti Marelli are known for high quality. You should choose the IAC valve only for the specific car brand and model. Important parameters are car production year, type and power of the engine installed in it. Technical characteristics of the idle air control valve depend on these parameters, for example, its operation mode (electrical or pneumatic), as well as type and quantity of connectors, presence of a gasket and so on.