Car engines rely on the idle air control, or IAC, valve to regulate airflow. The IAC regulates the airflow in the engine and helps to make idling smoother by connecting to the throttle.
Do you have trouble idling your Honda lately? Do you think the idle air control valve needs to be reset? This might solve your idling issue, but there is more to this.
During engine idling, the valve controls airflow even when the throttle is not being used. You can easily reset the idle air control valve on a Honda. It is possible, however, that the problem is more serious than this. Let’s begin with the basics.
What Is An Idle Air Control Valve?
It is a component of the engine attached to the throttle body called the idle air control valve. As the engine idles, the IAC manages the engine airflow electrically along with the engine control unit (ECU).
To maintain smooth operation when a car is stopped, the IAC valve injects air when the throttle plate closes.
Air circulates within the combustion area of the car through the IAC, bypassing the closed throttle plate. Therefore, it allows the car to idle smoothly because it bypasses the closed throttle plate.
The ECU also influences this process. For example, in the case of a parked or stopped vehicle, the computer system will activate the IAC valve automatically.
The valve will adjust itself to allow the required airflow into the combustion area once it receives the electrical signal.
What Is Engine Idle Speed, And How Is It Maintained?
When the engine is fully warmed up and the vehicle is in the park or neutral, the engine’s idle speed is measured in revolutions per minute (RPM).
Idle speeds are typically set between 600 and 800 RPM, depending on the number of cylinders and vehicle transmission type. The throttle body maintains idle speed in conjunction with the vehicle’s powertrain control module.
How Does An IAC Valve Work?
Located on the throttle body of fuel-injected engines, the idle air control (IAC) valve regulates airflow to the engine by electrically communicating with the vehicle’s engine control unit (ECU).
Is There A Reason Why Honda Idles High?
Listed below are some of the common causes of a high idle:
The Fuse Is Faulty
Idle control valves (ICVs) control engine idle speed in most vehicles. Idle Air Control (IAC) motor malfunctions due to faulty or blown fuses in other electronic control systems, leading to higher-than-normal engine idle speeds.
A Malfunctioning Computer
Idle speed may be affected if the powertrain control module malfunctions.
In addition to a high or low idle, an engine with a malfunctioning throttle system may stall. Air intake tubes that are dirty or cracked are often to blame.
Vacuum leaks will result in high engine idles on any engine because the oxygen sensor detects lean operations, and then the computer tries to compensate, causing abnormal idles.
How To Reset An Idle Air Control Valve?
You can reset your Honda’s idle air control (IAC) valve by following these steps:
- First, put slight pressure on the accelerator pedal.
- Then, run your engine for five seconds once you have done that.
- Next, for ten more seconds, turn off the ignition.
- Finally, restart the engine after 10 seconds.
You should now be able to idle your car correctly. However, it may be a sign of a larger issue with your engine or ventilation system if something still seems off. Consult a mechanic if this persists.
How Do I Tell If My Idle Air Control Valve Is Bad?
IAC valves play a crucial role in your engine’s overall performance. For example, when the throttle plate is closed, and the car is idle, the valve keeps circulating the right amount of air.
It is possible, however, that your car is not idling as smoothly as it used to or that your check engine light is on without knowing why. Idle air control valves are prone to malfunction for a variety of reasons.
A faulty IAC valve can also cause the following symptoms:
- There is a light on for the Check Engine.
- When the vehicle is idle, the RPMs increase.
- The car is stalling.
- When the engine is idle, the speed fluctuates randomly.
- Acceleration is poor.
- Unsmooth idling (engine sounds rough when stopped).
In the event of an IAC malfunction, you may damage your car’s engine if you don’t know the signs. There is also the possibility that the symptoms listed above may be a sign of another engine problem.
If you have concerns about the IAC valve, always seek professional advice. Of course, it is best to diagnose your car by a professional, but you can test and reset your IAC valve.
Honda Idle Speed Issues: When Should You Check Them?
You should consult a mechanic whenever you have concerns about parts of your car’s engine. You can, however, test the IAC valve yourself by turning the car on and listening to the engine while you are stopped.
- Holding The Vehicle At A Stop Requires Excessive Brake Effort
A very light force on the brake pedal will prevent forward motion if idle speed is normal.
- Engagement In The Drive Is Harsh
Putting the vehicle in drive when the idle speed is too high will result in it jumping forward.
- Idling Is Higher Than Usual
A mechanic can measure the engine speed with an instrument if the engine seems to be turning faster, but there is no RPM gauge.
- The RPM On The Dash Gauge Is Not Per OEM Specifications
RPM gauges are common in cars. Underhood labels specify the engine speed of the original equipment manufacturer (OEM). If that speed does not match the gauge, something is wrong.
Can You Drive With Incorrect Idle Speed?
Sadly, no. When you suddenly and unexpectedly increase your idle speed to high levels, you may experience unintended acceleration.
High idle speeds can make your vehicle difficult to control. It is more difficult to slow your vehicle down at a moderate idle speed, up to 1,200 RPM.
If you let your foot off the brake after the vehicle has stopped, the vehicle could continue forward. In addition to wasting gas, high idle speeds can be distracting since the vehicle does not perform as expected.
Is It Possible To Clean The Idle Air Control Valve?
It is possible to clean the idle air control valve. It is possible to clean the part either by removing it from the throttle body or while it is still in place. However, you must be careful with your cleaning products to remove carbon and debris.
When You Unplug The IAC, What Happens?
As long as the engine is idling, you can disconnect the IAC, and there shouldn’t be any damage. Nonetheless, when the engine is idling, the IAC valve plays a crucial role in keeping air flowing through the combustion chamber, and removing it may have adverse effects.
The Bottom Line
In a vehicle’s engine, the IAC valve plays an important role. The idle air control valve regulates the airflow into and out of the engine combustion chamber. The IAC valve is responsible for running your car’s engine smoothly when you stop it.
Damage and debris may cause issues with the valve, even though it is designed to last your entire vehicle’s life. In addition, your IAC valve may malfunction if your car is not idling properly.
To get your IAC valve working again, we have shown you how to reset it. However, it may be time to take your car to the mechanic if you’re still experiencing problems when it’s idling.