An idle air control (IAC) valve is a device that controls the amount of air that bypasses the throttle valve when the engine is idling. This allows the engine to maintain a consistent idle speed, even when the load on the engine changes. A faulty IAC valve can cause the engine to idle too high or too low, or to stall. Checking the IAC valve is a relatively simple procedure that can be done with a few basic tools.
The IAC valve is typically located on the throttle body or intake manifold. It is usually a small, round device with a black or gray plastic housing. To check the IAC valve, you will need a multimeter and a 12-volt power source. First, disconnect the electrical connector from the IAC valve. Then, connect the positive lead of the multimeter to the positive terminal of the IAC valve, and the negative lead of the multimeter to the negative terminal of the IAC valve. The multimeter should read 12 volts. If it does not, then the IAC valve is faulty and needs to be replaced.
