How to check iac using multimeter

В системе управления двигателя внутреннего сгорания одним из важных элементов является регулятор холостого хода. Качество его работы оказывает непосредственное влияние на эксплуатационные характеристики силовой установки. Отвечает устройство за расход топлива, стабильность холостых оборотов, вероятность того, что мотор внезапно не заглохнет. При такой ситуации необходимо знать, how to check idle sensor самостоятельно.


  • 1 What is the sensor idle control
  • 2 Sensor Diagnosis
  • 3 Ways to check the performance of the sensor
  • 4 Return to health node

What is the sensor idle control

It should be borne in mind that this node in the active phase remains almost all working hours. On this basis, the maximum resource of the product is limited by the mileage of the car at about 200–250 thousand km. In such a connection, most motorists are familiar with faults in the idling sensor. In modern gasoline cars, you can find two types of this node, structurally differing among themselves in the construction scheme:

  • direct throttle control;
  • adjustment of access to the bypass channel.

what causes idle sensor malfunction

The actuator in the device is a stepper motor. This is associated with significant advantages when compared with similar devices of a different type. The advantages are as follows:

  • high degree of accuracy;
  • minimum current consumption;
  • availability of pulse control mode.

In this case, during the absolute closing of the throttle valve, the rotational speed is maintained due to the additional suction through the bypass channel (bypass).

From the commands of the control unit of the power plant, the valve is moved. It also regulates the width of the valve clearance, which affects the air intake for the fuel-air mixture.

It is necessary to know that manufacturers select the optimal idle speed for each vehicle model, but usually the value is in the range of 600-1000 rpm.

Regulators of direct type of action on the valve are responsible for setting the maximum acceptable closing. A complete hermetic blockage does not occur, since a certain amount of air must be supplied to the intake manifold for the XX. Monitoring the number of revolutions traditionally carried out after a signal from the crankshaft sensor.

See also: How to check the starter on the battery with your own hands

what are the malfunction of the sensor idling

In diesel engines, the operation of this unit is provided by correcting the flow of fuel by the type of bypass - bypassing the engine. In this regard, high-pressure fuel pumps are equipped with a special electronic control system. The actuators are rotary valves or solenoids. It should be clarified that the actuators have only two types of positions closed / open.

Sensor Diagnosis

Identify the problem can be on different grounds. One of them is the CHECK ENGINE light bulb. However, a similar light signal appears in other cases. Check the regulator idle often relies on indirect signs, which include the following factors:

  1. Begin a noticeable problem of the work of the power plant at idle. After a short rotation, the motor starts to stall. This factor is encountered not only at the initial engine plant, but also on the way, for example, at a traffic light or other temporary stop.
  2. Turns are swimming. The idling sensor on the VAZ is able to demonstrate fluctuations in the range of 500-1000 rpm without driver intervention.
  3. During the start of a cold engine, elevated RPM is not felt, as was the case before.
  4. After moving to neutral and returning the pedal to the upper position, the motor may stall.

how to check ipx multimeter

You need to know that the symptoms of failure of the IAC are very similar to the partial or complete failure of the throttle position sensor. In this situation, the indicator light on the dashboard also lights up.

Ways to check the performance of the sensor

Sensor breakage is not a problem, as it can be replaced. However, it is preliminary recommended to check its real state. It is also desirable to identify the causes of malfunction of the idling sensor in order to prevent problems with the car in the future.

how to check idle sensor

Мониторинг осуществляется по следующей методике. Перед тем how to check ipx multimeter или другим прибором, находит датчик в подкапотном пространстве. Для выявления работоспособности переключаем мультиметр в положение контроля сопротивления. Включаем зажигание автомобиля и откидываем все подходящие провода от датчика.

See also: How to adjust the throttle

We test the resistance on each of the windings of the device. The correct values ​​are:

  • C - B no closure (open);
  • A - D no closure (open);
  • C - D within 30–1000 Ohm;
  • A - B in the range of 30-100 ohms.

A common cause of failure may be the jamming of the main working rod. This happens due to the penetration of moisture, small particles, dust and debris. All this leads to the emergence of corrosion and further malfunction. Such monitoring can only be carried out at a workshop using a pulse signal generator. Next comes the cleaning step.

Return to health node

After identifying the problems, it is worth to fix them. First of all, you need to clean the device from contamination. Do not immediately use aggressive tools such as WD40. It is preferable to start with less rigid substances such as neutral silicone greases. If the desired effect is not achieved, they gradually move to an increase in the chemical strength: alcohol, solvents, carburetor cleaning liquids, and only in extreme cases they leave “waddish”.

The method of partial soaking of the problem area is applied. Enough 10-15 minutes. In parallel, the bypass channel is cleared. It uses soft brushes from natural fiber.

If cleaning does not help, then a radical replacement is a complete remedy. Sometimes after installation of a new part in some cars calibration on special equipment is required. This operation is carried out in conditions of service.