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Audi S4 Idle Air Control Valve Replacement Costs
RepairSmith offers upfront and competitive pricing. The average cost for Audi S4 Idle Air Control Valve Replacement is $707. Drop it off at our shop and pick it up a few hours later, or save time and have our Delivery mechanics come to you.
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How Much Will An Idle Air Control Valve (IAC) Replacement Cost?
Generally, an idle air control valve or IAC valve replacement could cost anywhere from $120 to $500. This cost may vary as per the make and model of your vehicle, part price, and labor charges in your area.
The car part cost alone could set you back by $70 to $400, while a mechanic may charge $50 to $100 as labor charges. That said, the labor charges are usually low as the valve replacement doesn’t take long.
How Urgent Is An IAC Valve Replacement?
While you can continue to drive with a faulty idle air control valve, you ideally shouldn’t.
A bad IAC valve could cause your engine to stall, which can easily compromise your road safety. Also, if your vehicle’s Check Engine Light comes on due to a bad air control valve, you may not pass a state emissions test.
Bottomline — it’s best to get a faulty IAC valve replaced as soon as you spot one.
Signs Of A Failing Idle Control Valve
Several signs could indicate a bad idle control valve. But, these symptoms may also show up due to other engine troubles. In that case, it’s best to have a mechanic inspect your IAC valve to ascertain if that’s what is causing these symptoms.
Here are some signs that could give you a heads up about a faulty idle control valve:
An illuminated Check Engine Light: The Engine Control Module (ECM) will activate the Check Engine Light if the valve malfunctions. You’ll need an OBD-II scan tool to check if the light is illuminated due to a faulty IAC valve.
Fluctuating idle speed: The idle control valve manages your engine’s RPM rate to maintain idle speed. In case of a bad valve, the RPM could go high above 1,100 RPM or below 700 RPM, or keep fluctuating. Sometimes vacuum leaks could also cause an elevated idle RPM.
Engine stalling: Anything like turning on the AC or a change in elevation could cause your engine to stall if the idle air control valve can’t adjust to different driving conditions.
Backfiring: When the engine doesn’t get enough air, the air-fuel ratio will run rich. As a result, the excess fuel in the system could cause a backfire.
Car starts, then dies: If the valve only works in certain parts of its cycle, the engine might start briefly before it dies due to lack of air.
4 FAQs On The Idle Air Control Valve
Here are answers to some common IAC valve-related queries:
1. What’s An Idle Air Control Valve?
An idle air control valve, also known as an idle air control actuator, is usually used in fuel-injected vehicles. Its role is to control the airflow needed in the combustion engine to maintain a steady idle speed. Essentially, the valve acts as a bypass of the throttle body plate.
Your vehicle’s Engine Control Module digitally monitors the idle control valve to maintain the required idling RPM irrespective of the driving conditions or engine load.
This lets you move your car from an idle position by simply releasing the clutch or brake.
2. Where is an Air Control Valve Located?
The idle control valve is usually located on the intake manifold near the back of the throttle body. The intake manifold is the engine part that supplies the air-fuel mixture to the cylinders.
Most modern cars today have the valve integrated into the throttle body.
3. What Causes An IAC Valve To Fail?
While an IAC valve has a reasonably long life, it could malfunction prematurely. Some of the common reasons for its failure are:
Clogged IAC valve: Over time, contaminants could enter the valve chamber and clog or jam its internal parts.
Failing IAC valve: The solenoid inside the valve could fail and not send a signal to your vehicle’s ECM. As a result, your car won’t start.
4. How To Perform An Idle Air Control Valve Replacement?
While replacing an idle air control valve is relatively easy, you still need to know your car parts well. If you’re not sure, it’s best to have a certified technician do the replacement for you.
Here’s how a mechanic will replace an idle control valve:
Park the car on a flat surface.
Once the engine is cooled down, open the hood and locate the idle air control valve.
Remove any other parts that come in the way of accessing the valve.
Unplug the valve’s electrical connector.
Remove the old idle air control valve.
Remove the old gasket and ensure that no gunk is left behind.
Install the new idle air control valve with a new gasket.