The idle air control (IAC) valve manages the idle speed of your engine by controlling the amount of air that flows into the engine. Needless to say, while the engine requires an optimal amount of air and fuel to function efficiently, a faulty idle air control valve can throw the air supply off and adversely affect the engine’s performance.
It is essential to attend to the idle air control valve as soon as your vehicle starts showing symptoms of a failing valve. Symptoms include the vehicle struggling to start, rough idling, stalling, and backfiring.
Read on to learn the most common bad idle air control valve symptoms.
Symptoms Of Bad Idle Air Control Valve
There are several ways your vehicle could tell you its idle air control valve is in trouble. Know, however, that these symptoms are quite general and are not 100% accurate diagnoses. If you inspect, clean, or replace, your valve, the idle issues might persist due to other problems within the engine.
Here’s what to look out for:
#1. Irregular or fluctuating idle speed.
A clear sign of an IAC valve problem is when your engine’s idle speed fluctuates, sometimes quite dramatically. You might notice the tachometer bouncing around, and the engine may sound like it’s sputtering.
#2. Hard engine starts.
A faulty IAC valve can lead to difficulty in starting your car, especially in cold conditions. Erratic idling can prevent the engine from finding a stable speed for successful ignition.
#3. Engine stalling.
If your vehicle stalls when you come to a stop or when idling, it can be a result of a bad IAC valve. The valve may be failing to regulate the idle air properly, which means the engine may not have enough air to continue running smoothly.
#3. Poor performance.
A vehicle experiencing a loss of power or misfiring when accelerating may have an IAC valve issue. This symptom is often more noticeable when you hit the gas to increase speed or climb hills.
#4. Check Engine Light On.
The IAC valve’s performance is continuously monitored by the engine control module. When the module detects an issue, it will trigger the Check Engine light to warn you of a potential problem.
#5. Car Starts, Then Dies.
If the valve works occasionally, or it only works in certain parts of its cycle, the car might be able to start before it starves of air and dies.
#6. Backfiring.
If the engine doesn’t have enough air, the air-to-fuel mixture ratio is off, and some fuel might be left after the spark. This fuel then makes its way through the system and could cause a backfire.
How Do You Know If The Idle Air Control Valve Is Bad?
There is one simple way to identify that your vehicle has a bad idle air control valve. With the help of a voltmeter, you can determine that there is a need to replace the voltmeter or not.
Make sure you have the right tools in hand before you proceed with testing the idle air control valve
Before you proceed, you need to buy automotive tools that are necessary for checking the idle air control valve: Voltmeter, Screwdriver, Socket wrench, 10mm socket.
Here is what you need to test the idle air control valve:
- Open the hood and you will find the valve behind the engine
- With the help of the screwdriver unscrew the valve from the throttle body
- Squeeze the release tab and unplug the electrical plug of the idle air control valve
- Flip the valve so that you can see its openings
- Set the voltmeter to “Ohms”
- Put one lead of the voltmeter at one end of the control valve’s terminal and do the same for another end.
- If the readings are not between 0.00 and 0.05 then your vehicle has a bad air control valve and needs to be replaced.
Now you know the symptoms of a failing idle air control valve. Thus, if you come across all or any of the above-discussed symptoms of a faulty idle air control valve, then don’t delay taking your car to an auto service centre at the earliest. One
FAQs.
What happens when the idle air control valve goes bad?
You might notice the tachometer bouncing around, and the engine may sound like it’s sputtering. Hard engine starts – A faulty IAC valve can lead to difficulty in starting your car, especially in cold conditions. Erratic idling can prevent the engine from finding a stable speed for successful ignition.
How do you check the idle air control valve?
To check whether the idle air control valve is functioning properly, start the engine and let it run for about 10 to 15 minutes. If the valve is functioning correctly, the engine will sound good and the idle will be steady versus too high, too low, or inconsistent.
Is it bad to drive with a bad IAC valve?
Technically, you can still drive with a bad IAC, but driving with a bad idle air control valve is not recommended. It can commonly lead to engine stalling, which can compromise vehicle safety. Furthermore, note that you won’t pass a state emissions test if the check engine light is on due to a faulty valve.
How long do idle air control valves last?
IAC valves should last as long as your car, but sometimes it needs to be replaced or maintained. Here are just some of the signs that you have a faulty IAC valve: Your engine light comes on – this is the most obvious way to tell if any of your car’s components are malfunctioning.
What is the code for idle air control valve trouble?
DTC P0511 stands for “Idle Air Control Circuit,” and it is logged when the PCM detects a problem with your vehicle’s idle air control system. Code P0511 is commonly caused by a failed idle air control valve, engine vacuum leaks, or carbon buildup on the throttle body or air control valve.