Idle air control valve location

Tiny
PAIGE HEINZMANN
  • MEMBER
  • 1999 FORD F-250
  • 5.4L
  • V8
  • 4WD
  • AUTOMATIC
  • 127,000 MILES
Where is the location of the idle air control valve?
Saturday, May 18th, 2019 AT 9:40 AM

14 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good afternoon,

The IAC is on top of the throttle body. I attached pictures for you to view the location. Check out the diagrams (Below). Please let us know if you need anything else to get the problem fixed.

Roy
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Saturday, May 18th, 2019 AT 10:54 AM
Tiny
MUSSER1987
  • MEMBER
  • 1 POST
  • 1993 FORD F-250
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 118,000 MILES
Where is the iac on this vehicle and how do you replace it?
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Friday, October 16th, 2020 AT 1:42 PM (Merged)
Tiny
IMPALASS
  • MECHANIC
  • 3,112 POSTS
Hello
Here is the info you requested


https://www.2carpros.com/forum/automotive_pictures/248015_1_84.jpg



REMOVAL

Disconnect negative battery cable.
Disconnect the Idle Air Control (IAC) valve assembly connector from the wiring harness.
Remove the two IAC valve retaining bolts.
Remove the IAC valve and gasket.


https://www.2carpros.com/forum/automotive_pictures/248015_2_46.gif



INSTALLATION

NOTE: If scraping is necessary, be careful not to damage sealing areas of IAC valve or throttle body gasket surfaces, or drop material into throttle body, or intake manifold.

Make sure that both throttle body and IAC valve gasket surfaces are clean.
Install gasket and IAC valve.
Install retaining screws. Tighten to 8-11 Nm (71-97 in lb) .
Connect electrical connector for the IAC valve.
Reconnect negative battery cable. NOTE: When the battery has been disconnected and reconnected, some abnormal drive symptoms may occur while the powertrain control module relearns its adaptive strategy. The vehicle may need to be driven 10 miles or more to relearn the adaptive strategy.
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Friday, October 16th, 2020 AT 1:42 PM (Merged)
Tiny
JAM39
  • MEMBER
  • 4 POSTS
  • 1989 FORD F-250
  • V8
  • 2WD
  • AUTOMATIC
  • 135,000 MILES
Why do I not have 10.5 volts from PCM to IAC sensor.
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Friday, October 16th, 2020 AT 1:42 PM (Merged)
Tiny
CARADIODOC
  • MECHANIC
  • 33,864 POSTS
What's the symptom?

It's not a sensor; it's an output. The higher the voltage, the further it opens to allow in more air to control idle speed.

Caradiodoc
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Friday, October 16th, 2020 AT 1:42 PM (Merged)
Tiny
JAM39
  • MEMBER
  • 4 POSTS
Why am I missing voltage to my IAC from the PCM
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Friday, October 16th, 2020 AT 1:42 PM (Merged)
Tiny
CARADIODOC
  • MECHANIC
  • 33,864 POSTS
Sometimes there is not supposed to be voltage to it. The higher the voltage, the higher the Engine Computer is trying to raise engine speed.

What is the symptom? Does the engine stall? Will it run if you hold the gas pedal down a little? Is the engine running too fast at idle? Need to know what the symptom is, otherwise, the system could be working normally.

Caradiodoc
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Friday, October 16th, 2020 AT 1:42 PM (Merged)
Tiny
JAM39
  • MEMBER
  • 4 POSTS
I recently cleaned to upper intake including the IAC
control, and before cleaning the idle was a much
higher RPM and decreased when engine reached
normal op temp.
I read in a HAYNES repair manual that the IAC should
have 10.5 volts with key on engine off.
I hope this helps.
Jim
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Friday, October 16th, 2020 AT 1:42 PM (Merged)
Tiny
CARADIODOC
  • MECHANIC
  • 33,864 POSTS
First of all, I messed up. The control wire gets grounded by the Engine Computer. It doesn't apply voltage on the control wire.

I spoke with a Ford expert who said they don't normally check for this voltage. If the system is working properly, the engine will stall when the IAC is unplugged. If stalling does not occur, suspect a vacuum leak.

You might also measure the voltage on the connector when it's unplugged from the IAC unit. If it is there, but not when it's plugged in, look for a corroded spot in the wire, typically a pin in a connector. If the voltage is still missing, measure on that wire at the Engine Computer connector.

Caradiodoc
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Friday, October 16th, 2020 AT 1:42 PM (Merged)
Tiny
JAM39
  • MEMBER
  • 4 POSTS
Thanks very much for your help.

Jim
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Friday, October 16th, 2020 AT 1:42 PM (Merged)
Tiny
ROADGEAR
  • MEMBER
  • 2 POSTS
  • 1988 FORD F-250
  • 197,000 MILES
Changed IAC valve from another truck and it ran fine for 10mins, then jumped up to 2200 rpms again. Can not do codes yet as today is Sunday, will do tomorrow. Other truck runs fine with old IAC valve reinstalled in it. Driving me nuts. Should I wait for codes then contact you again? Thanks alot for the help so far. Bill
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Friday, October 16th, 2020 AT 1:42 PM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Why did you replace it to begin with?

Roy
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Friday, October 16th, 2020 AT 1:42 PM (Merged)
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
You should be replying to your previous post as the person attending to you can't be running around looking for you.
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Friday, October 16th, 2020 AT 1:42 PM (Merged)
Tiny
ROADGEAR
  • MEMBER
  • 2 POSTS
Sorry guys. Just new here
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Friday, October 16th, 2020 AT 1:42 PM (Merged)

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