How To Reset Idle Air Control Valve

Download Article

The idle air command valve — also known equally the "idle speed control valve" — regulates the idle speed of your engine. This is controlled by the engine's computer. Sometimes parts become bad, which results in your car idling strangely or stalling. Check to see if your idle command valve is performance properly earlier attempting to replace it.

1
Look for a high engine idle. A mutual symptom of a faulty idle control valve can be a high idle. Start the engine and look at the tachometer on the dashboard. Most vehicle'south engines will idle at our below one thousand RPMs. If you are familiar with your engine's normal idle, compare that to its current RPMs.^[1]
- If the vehicle's engine is idling well above 1,000 RPMs, it's probably also loftier.
- Vacuum leaks can also cause a loftier idle.
ii
Pay attention to depression idle or stalling. Aside from high 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 finish to how information technology normally runs. ^[ii]
- If the idle is low and inconsistent, it may be due to an issue with your idle control valve.
- Depression idles could also be caused by vacuum leaks.
Advertisement
three
Look for signs of a vacuum leak. If your engine is idling poorly, try to diagnose any possible vacuum leaks that may exist causing information technology. Visually audit the vacuum lines in your engine bay for signs of harm such as cracks or overly worn areas.^[three]
- Remove a vacuum line and connect information technology to a vacuum gauge to measure the level and consistency of the vacuum.
- Yous can besides try spraying a soap and water mixture on the lines to await for bubbling at the indicate of a leak.
four
Have note if the check engine light comes on. The check engine light in your vehicle is designed to plow on if the Engine Command Unit (ECU) identifies an problems with how the engine is running. Look at your dashboard; if the check engine light is on in conjunction with idle issues, it may exist considering the idle command valve is malfunctioning.^[iv] ^[five]
- The check engine light looks similar a uncomplicated cartoon of an engine.
- A check engine light in conjunction with idle bug can be indicative of a faulty idle control valve.

Advertizement

ane
Use a lawmaking scanner to check error codes. If your vehicle was congenital prior to 1996, you will need an OBD I scanner. Vehicles made after 1996 will demand an OBD II scanner.^{[half dozen]} Connect the code scanner to the port beneath the dashboard and turn it on. One time continued, employ the scanner to bring upwardly the error codes making the check engine light come up on.^[7]
- In some code scanners, it volition provide the English language description of the mistake lawmaking on the read out.
- If your code scanner does not, yous will need to await up the code the scanner shows y'all to find out what information technology is.
ii
Start the engine and have note of the idle RPMs. Insert the cardinal into the ignition and start the engine. Look a infinitesimal for the engine idle to level off, then use a pen and paper to write down the RPMs that your engine settles and idles at.^[8]
- You may need to permit the engine run for a few minutes in society for information technology to come down to its normal idle speed.
- Keep the newspaper you write the RPMs on handy and then yous tin can compare it to the engine's idle as you lot continue the test.
3
Close the motorcar off and disconnect the Idle Command 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 Command Motor. Once you locate it, disconnect it.^[ix]
- The way to disconnect your Idle Control Motor volition vary from application to awarding; refer to your vehicle's service manual for more than specific instruction equally to how to disconnect it.
- You can usually disconnect the idle control motor by unplugging the wiring clip going into it.
4
Restart the engine. With the Idle Command Motor asunder, become dorsum into the vehicle and start the engine over again. The engine should notwithstanding start and run without whatsoever issue despite the idle control motor being asunder.^[10]
- Be sure to tuck the wiring you lot disconnected up in the engine bay and so it doesn't go defenseless in any moving parts.
5
Look for a difference in idle speed. Permit the engine to run for a minute so it settles to a consequent idle, so take annotation of any difference in the idle RPMs versus the idle you lot observed before. If the idle has not changed at all, it'south likely because your idle control motor has not been performance.^[11]
- If the idle command motor was working, disconnecting it should have created a deviation in the engine's idle.
- This test confirms in that location's an upshot with the idle control motor, only not what the issue may be.
6
Shut off the engine and reconnect the Idle Control Motor. If you identified a difference in engine idle RPMs with the Idle control motor connected and disconnected, confirm your hypothesis by reconnecting it and starting the engine again.^[12]
- The idle should get back to what information technology was when the idle control motor was final continued.
- Refer to the note you took nearly idle RPMs to compare it to your first reading.

Advert

1
Use a test low-cal to check the wiring on a GM idle command motor. Take a test lite and connect the negative lead to the trunk of the vehicle. Printing the exam lite into each of the 4 circuits on the GM idle control motor. Each circuit should make the exam lite flash or become from brilliant to dim while the engine is running.^[13]
- If the exam calorie-free doesn't flash on each excursion, the issue is coming from the ECU, not the idle control motor.
- If the test light flashes properly, information technology ways the idle command motor needs to exist replaced.
2
Mensurate the resistance of the solenoid in a Ford. Locate the idle control motor in your Ford vehicle and identify the two electrical pins on the solenoid. Connect an Ohm meter to the two and measure 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 exterior that range, the idle command motor needs to exist replaced.
3
Use a bidirectional scan tool to increment idle speed in a Chrysler. Connect a bidirectional scan tool to the same OBD port yous would plug a lawmaking scanner into. Use the command in the scan tool to increase the engine'due south idle. If the engine idle does not increase, information technology means in that location is an consequence at the idle control motor of its circuit preventing the signal from changing the idle.^[15]
- Y'all can purchase a bidirectional scan tool at your local car parts store.
- Make sure the wiring harness is firmly connected to the idle command motor before conducting this exam.

Advert

Add New Question

Question

How do I know if my vehicle has a problem with the idle air control valve?

Hovig Manouchekian is an Machine Repair and Design Specialist and the Managing director of Funk Brothers Automobile, a family unit-owned business operated since 1925. With over xxx years of experience in the automotive industry, Hovig specializes in the process of auto repair and maintenance. He is also very knowledgeable in common automotive issues and needs including engine repair, battery replacement, and windshield accessory and maintenance. Hovig's knowledge and hard work have contributed to Funk Brothers Auto winning Angie's List Super Service Honour for v consecutive years.

Auto Repair & Design Specialist

Adept Answer

If your cheque engine calorie-free is on, that may assist with the diagnosis. Also, if you have a modern vehicle with an OBD2 organization, you can bank check your idle air through browse tools. On older vehicles, try to check the resistance that'south going to the valve from the vehicle. You can also try to manually activate it to encounter how the car reacts—yous may be able to isolate the problem to the valve.
Question

When I slow down or when I stop at a red low-cal my machine dies. Could this be due to the idle air command valve?

It's possible. A faulty idle control valve can get out the engine idling at likewise depression an RPM for it to continue running.
Question

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

It'southward possible that a faulty idle command valve can leave the engine idling at too depression an RPM for it to continue running.
Question

What would crusade my auto that idles fine not to idle down when coming to a finish? The IAC has been replaced.

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

Would bad ICV make the auto hard to get-go after it has run for a time?

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

What could the trouble with my car be when information technology wants to idle way too slowly?

Nick Florence

Community Answer

If your idle is also low, it could exist the IAC not talking to the computer correctly. Disconnect the IAC connector for a couple seconds while your engine is idling. If your engine idle didn't change, you can suspect information technology to be the IAC. If it is working properly, unplugging it would cause your idle to freak out. As well check the wires going to the IAC connector.
Question

Tin can a bad idle air control valve cause the RPM to idle a picayune high and come downwards slowly to normal rpm range?

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

I take 98 Contrivance Caravan Sport with a 3.iii V6. It has a rough idle at start, the check engine light is on, and the idle corrects itself usually after 20 to 30 seconds. I can likewise right the problem by disconnecting a vacuum line for a few seconds. What could be wrong with my engine?

Ready the Check Engine Light first, Yous tin can get a reader for gratis at autoparts store. In one case you know what the code says, you can outset figuring out solutions.
Question

Is in that location whatsoever risk using automobile with idle control problems?

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

How do I understand machine error codes?

Google the code along with the make of your vehicle, i.due east. "Toyota P0505" for OBDII or "Ford 214" for OBDII.

Show more answers

Ask a Question

200 characters left

Include your electronic mail address to go a message when this question is answered.

Submit

Nigh This Article

Article Summary X

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

Did this summary help you?

Thank you to all authors for creating a page that has been read 1,082,490 times.