How To Change The Idle Air Control Valve

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The idle air command valve — likewise known every bit the "idle speed control valve" — regulates the idle speed of your engine. This is controlled by the engine'south reckoner. Sometimes parts go bad, which results in your automobile idling strangely or stalling. Check to come across if your idle control valve is functioning properly before attempting to supervene upon it.

1
Expect for a high engine idle. A mutual symptom of a faulty idle command valve tin can be a loftier idle. Start the engine and look at the tachometer on the dashboard. Most vehicle'southward engines will idle at our below one thousand RPMs. If you are familiar with your engine'south normal idle, compare that to its current RPMs.^[1]
- If the vehicle's engine is idling well above 1,000 RPMs, it's probably too high.
- Vacuum leaks tin also cause a high idle.
2
Pay attention to low idle or stalling. Aside from loftier idle issues, low idle and even sporadic stalling can both exist attributed to a bad idle control valve. Again, start the engine and compare how it is running at a stop to how it normally runs. ^[2]
- If the idle is depression and inconsistent, information technology may be due to an result with your idle control valve.
- Low idles could as well be caused by vacuum leaks.
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3
Look for signs of a vacuum leak. If your engine is idling poorly, try to diagnose whatsoever possible vacuum leaks that may be causing it. Visually inspect the vacuum lines in your engine bay for signs of damage such as cracks or overly worn areas.^[3]
- Remove a vacuum line and connect it to a vacuum judge to measure the level and consistency of the vacuum.
- You can besides endeavor spraying a soap and water mixture on the lines to look for bubbling at the point of a leak.
4
Take note if the check engine light comes on. The check engine low-cal in your vehicle is designed to turn on if the Engine Control Unit of measurement (ECU) identifies an issues with how the engine is running. Look at your dashboard; if the check engine light is on in conjunction with idle issues, information technology may be because the idle control valve is malfunctioning.^[4] ^[5]
- The check engine lite looks like a uncomplicated cartoon of an engine.
- A cheque engine light in conjunction with idle problems tin be indicative of a faulty idle command valve.

1
Use a code scanner to bank check error codes. If your vehicle was built prior to 1996, you will demand an OBD I scanner. Vehicles made afterwards 1996 volition need an OBD Ii scanner.^[six] Connect the lawmaking scanner to the port below the dashboard and turn it on. In one case continued, utilise the scanner to bring upwards the error codes making the check engine light come on.^[7]
- In some code scanners, it volition provide the English description of the error lawmaking on the read out.
- If your code scanner does not, you lot will need to look up the code the scanner shows you to find out what it is.
two
Offset the engine and take note of the idle RPMs. Insert the primal into the ignition and start the engine. Look a minute for the engine idle to level off, then use a pen and paper to write downwards the RPMs that your engine settles and idles at.^[8]
- You may need to allow the engine run for a few minutes in guild for it to come down to its normal idle speed.
- Proceed the paper you write the RPMs on handy so you tin compare information technology to the engine's idle as you lot go along the examination.
iii
Close the car off and disconnect the Idle Control Motor. With the idle RPMs noted, close the vehicle back off and remove the key from the ignition. Open the hood and locate the Idle Control Motor. Once you locate it, disconnect it.^[9]
- The fashion to disconnect your Idle Control Motor volition vary from application to application; refer to your vehicle's service manual for more than specific pedagogy every bit to how to disconnect it.
- You lot can usually disconnect the idle control motor past unplugging the wiring prune going into it.
4
Restart the engine. With the Idle Control Motor disconnected, get back into the vehicle and start the engine over again. The engine should still start and run without any issue despite the idle control motor beingness asunder.^[10]
- Be sure to tuck the wiring you asunder upward in the engine bay so information technology doesn't get caught in any moving parts.
5
Wait for a difference in idle speed. Permit the engine to run for a minute then it settles to a consistent idle, then accept note of any divergence in the idle RPMs versus the idle you observed earlier. If the idle has non changed at all, information technology's likely because your idle control motor has non been functioning.^[xi]
- If the idle control motor was working, disconnecting it should have created a divergence in the engine's idle.
- This exam confirms there'due south an issue with the idle control motor, merely not what the result may exist.
6
Shut off the engine and reconnect the Idle Command Motor. If you identified a difference in engine idle RPMs with the Idle control motor connected and asunder, ostend your hypothesis past reconnecting it and starting the engine again.^[12]
- The idle should go back to what it was when the idle control motor was last connected.
- Refer to the note you took nearly idle RPMs to compare information technology to your first reading.

1
Use a exam low-cal to check the wiring on a GM idle control motor. Accept a exam light and connect the negative lead to the body of the vehicle. Printing the examination lite into each of the four circuits on the GM idle command motor. Each excursion should make the test light wink or get from brilliant to dim while the engine is running.^[13]
- If the exam calorie-free doesn't wink on each circuit, the consequence is coming from the ECU, not the idle command motor.
- If the test low-cal flashes properly, it means the idle control motor needs to be replaced.
2
Measure the resistance of the solenoid in a Ford. Locate the idle control motor in your Ford vehicle and place the two electric pins on the solenoid. Connect an Ohm meter to the 2 and mensurate the resistance between them.^[14]
- Fords are designed to operate with the resistance in the solenoid in a range between 7.0 to 13.0 ohms.
- If the resistance is outside that range, the idle control motor needs to be replaced.
iii
Utilize a bidirectional scan tool to increase idle speed in a Chrysler. Connect a bidirectional scan tool to the aforementioned OBD port yous would plug a lawmaking scanner into. Use the command in the scan tool to increase the engine's idle. If the engine idle does not increase, it means there is an issue at the idle command motor of its circuit preventing the signal from changing the idle.^[15]
- Y'all tin buy a bidirectional scan tool at your local auto parts store.
- Brand sure the wiring harness is firmly continued to the idle control motor earlier conducting this test.

Add together New Question

Question

How practice I know if my vehicle has a trouble with the idle air control valve?

Hovig Manouchekian is an Auto Repair and Design Specialist and the Managing director of Funk Brothers Auto, a family-endemic business operated since 1925. With over xxx years of experience in the automotive manufacture, Hovig specializes in the process of motorcar repair and maintenance. He is besides very knowledgeable in common automotive issues and needs including engine repair, bombardment replacement, and windshield accessory and maintenance. Hovig'due south cognition and hard piece of work have contributed to Funk Brothers Auto winning Angie's List Super Service Award for five consecutive years.

Car Repair & Design Specialist

Skillful Reply

If your check engine low-cal is on, that may aid with the diagnosis. Too, if y'all take a modern vehicle with an OBD2 arrangement, you tin can check your idle air through browse tools. On older vehicles, try to check the resistance that'south going to the valve from the vehicle. Y'all can also try to manually activate it to see how the auto reacts—you may be able to isolate the problem to the valve.
Question

When I tiresome down or when I terminate at a red light my automobile dies. Could this be due to the idle air control valve?

It'southward possible. A faulty idle control valve tin can go out the engine idling at also low an RPM for it to continue running.
Question

The engine only runs when my foot is on the gas pedal. What's the deal?

It'south possible that a faulty idle control valve can leave the engine idling at too low an RPM for information technology to keep running.
Question

What would crusade my car that idles fine non to idle down when coming to a end? The IAC has been replaced.

If replacing the ICV or IACV and problems still persist, test all the vacuum hose lines equally mentioned in the steps above using soapy water.
Question

Would bad ICV brand the car hard to showtime afterward information technology has run for a time?

No. The idle control valve should have very little to do with how the vehicle starts.
Question

What could the problem with my car exist when it wants to idle mode too slowly?

Nick Florence

Customs Answer

If your idle is too depression, it could be the IAC not talking to the reckoner correctly. Disconnect the IAC connector for a couple seconds while your engine is idling. If your engine idle didn't change, you can doubtable it to be the IAC. If it is working properly, unplugging it would cause your idle to freak out. Also check the wires going to the IAC connector.
Question

Can a bad idle air command valve cause the RPM to idle a little high and come down slowly to normal rpm range?

Normally, if you just start your car, the idle air control valve will cause the engine rpms to increment and slowly decrease. That would exist a sign that your IAC is working.
Question

I have 98 Dodge Caravan Sport with a iii.3 V6. It has a crude idle at commencement, the check engine light is on, and the idle corrects itself ordinarily after xx to 30 seconds. I can also correct the problem by disconnecting a vacuum line for a few seconds. What could be incorrect with my engine?

Fix the Check Engine Calorie-free first, You can become a reader for free at autoparts store. Once you know what the code says, y'all tin first figuring out solutions.
Question

Is there whatsoever risk using car with idle control problems?

Not usually. The idle control valve only effects the engine while your pes is not on the gas. As long every bit the vehicle isn't idling at too high an RPM or stalling, it should function with a faulty idle control valve.
Question

How exercise I understand auto error codes?

Google the code along with the brand of your vehicle, i.e. "Toyota P0505" for OBDII or "Ford 214" for OBDII.

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Commodity Summary Ten

To bank check if an idle control valve is working properly, start by turning on your engine and letting it run for a minute or 2. And then, when information technology'south at an idling speed, take note of the RPMs in your car. Next, turn the engine off and disconnect the idle command motor under your hood. Once it's asunder, tuck the wire out of the mode, restart your car, and await a minute or 2 earlier checking your RPMs. If your RPMs are the same both times, your idle control valve isn't working. For tips on how to check an idle air command valve in a GM or Ford car, read on!

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