Idle air control valve test

When the engine has a high or low idle speed or shuts down, the cause may be the control valve and an idle air control valve test should be performed. In addition to the air control valve, the cause may be a dirty intake line in the throttle part or a leak in the intake manifold.

Testing the idle air control valve is in a few steps.

If the fault light is on, reading fault codes through diagnostics directs us to the cause of the malfunction.

The next step is to check the rpm engine with and without the idle air control valve. Start the engine and record the engine idle speed. Stop the engine, the removed plug from the idle air control valve, and the restarted engine. If the rpm is the same without the valve, the problem is most likely in the idle air control valve itself. However, if the rpm increases, the idle air control valve is correct.

When, after the test of disabling the operation of the idle air control valve, there is doubt about its correctness, a visual inspection of the valve. Remove the idle air control valve. The installation site and valve are visually inspected for soot, rust or dirt. Also, check the valve shaft. Cleaning is done with a suitable means for removing impurities. They can damage the walls, ducts and valve and thereby change the function of the idle speed regulator.

The next step is to check the electrical functions. The resistance of the valve winding is measured with an ohmmeter and compared with the actual value. If the resistance is outside the set value, the regulator is faulty. The control signal from the ECU is checked using a test light. The valve is unplugged. Connect the negative lead of the test light to the chassis vehicle. The engine starts. The tip of the test light is connected to each terminal of the socket. The test light should flash when plugged in. If it does not flash, the problem is in the supply of the control signal.

To test the idle air control valve, follow these steps:

Fault diagnosis

Connect the diagnostic tool to the vehicle. Read and analyze fault codes. If the fault code refers to the idle air control valve or the regulation of the idle speed, proceed to check the valve and other elements that may be the cause of the failure.

Testing by switching off the valve

Start the engine and read the idle speed. Turn off the engine. Remove the electrical socket from the idle air control valve. Start the engine again and read the idle speed. If the read values are the same, continue testing the idle air control valve.

Visual inspection

Remove the idle air control valve from the intake manifold. Visually check the valve installation site for dirt. Inspect the valve and valve shaft. If there are impurities, apply a suitable agent and clean without scraping. If damage is detected, replace the idle air control valve.

Electrical testing

Measure the resistance of the valve coil with an ohmmeter. If they are outside the actual values, replace the idle air control valve. With the valve socket removed, start the engine. Connect the minus conductor of the test light to the chassis of the vehicle, and connect the plus to each connector of the socket in turn. The test light should be flashing, otherwise, the problem is in the supply of the control signal to the idle air control valve.