What are the effects of a faulty idle control valve?

1 Answers
OPaige
07/29/25 8:56am
If the idle control valve is faulty, the car may emit a strong gasoline odor and experience jerking when the engine is warm. Issues with the idle control valve: When the idle speed exceeds the set speed, the ECU commands the idle control valve to reduce the intake bypass channel, decreasing the air intake and lowering the engine speed. Problems such as sticking due to oil residue or carbon buildup, or incomplete throttle closure, can prevent the ECU from correctly regulating the engine idle, leading to unstable idle speed. Intake manifold leaks: The opening of the idle control valve and the air intake strictly follow a certain functional relationship—that is, as the idle control valve opening increases, the air intake correspondingly rises. A leak in the intake manifold disrupts this relationship, causing the air intake to no longer strictly adhere to the original function. As a result, the air flow sensor cannot accurately measure the real intake volume, leading to inaccurate ECU control of the air intake and unstable engine idle speed.
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