Many car owners who are independently engaged in repairing their cars and who are first faced with unstable engine idling, in search of information on the topic, turn to the World Wide Web and most often receive unambiguous advice on replacing the idle sensor from the regulars of auto forums. However, if you are not the owner of an exclusive foreign car or a used Lunokhod of 1969 model, you should know: you will not find any idle speed sensor under the hood of your swallow …
The point is that finding an idle sensor in a car is equivalent to finding a black cat in a dark room - in both cases, the item you are looking for simply does not exist! The idle speed regulator (this is the correct name for this element of the control system) belongs to the category of actuators, which is far from the same as the sensor. Its task includes the functions of maintaining a given engine speed by closing the so-called bypass air channel, which regulates the air flow bypassing the throttle valve.
How does the idle speed regulator work?
Structurally, the IAC is a stepper motor with two windings controlled by a pulse voltage, which is formed by special drivers included in the control unit. Unlike a conventional rotary electric motor, the supply of voltage does not cause the shaft to rotate, but its movement in the longitudinal direction in one direction or another. A plastic cone-shaped plug is fixed to the rod (shaft) of the engine, which changes the section of the air bypass channel. It is very problematic to unequivocally assess the serviceability of the IAC without special equipment, but if the engine is unstable at idle, and jerks and dips are felt during movement, then this is a reason to think about replacing the IAC.
Where can I find IAC?
For visual detection of IAC is sufficient to find the eye-catching air filter and trace the direction of the thick rubber pipe, air inlet to throttle knot.
The location of the XX regulator in different cars, of course, is different, but, as a rule, it is installed directly on the throttle assembly, inside which the damper of the same name is located.
On the same node is located the throttle position sensor TPS, which looks similar to the IAC.
Not to confuse IAC with the TPS, remove the connector from one of them and estimate the number of contacts. If the three of them, then it's the TPS, if the four - IAC.
By the way, when replacing the IAC, most often it is necessary to remove the entire throttle assembly due to the fact that the mounting features do not allow its dismantling directly on the engine. It is most convenient to find the necessary information on the sequence of operations in the step-by-step illustrated instructions for your car model, but if you do not have the necessary skills, it is better to contact the service department.
