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P1504 Ford Code - Intake Air Control Circuit Malfunction

Quick Answer

The Idle Air Control Valve (IACV) valve assembly controls the engine idle speed and provides a dashpot function. Common causes include Faulty Idle Air Control Valve, Idle Air Control Valve harness is open or shorted, Idle Air Control Valve circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P1504 Ford indicates Intake Air Control Circuit Malfunction.
Common causes
Common causes include Faulty Idle Air Control Valve, Idle Air Control Valve harness is open or shorted, Idle Air Control Valve circuit poor electrical connection.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
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Code Popularity 112,475
How popular is this code, among other codes? Medium
What is this?
Table of contents Created and updated by William Orellana on Aug 25, 2019
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Code P1504 Ford Description

The Idle Air Control Valve (IACV) valve assembly controls the engine idle speed and provides a dashpot function. The IAC valve assembly meters intake air around the throttle plate through a bypass within the IAC valve assembly and throttle body. The Powertrain Control Module (PCM) determines the desired idle speed or bypass air and signals the IAC valve assembly through a specified duty cycle. The IAC valve responds by positioning the IAC valve to control the amount of bypassed air. The PCM monitors engine RPM and increases or decreases the IAC duty cycle in order to achieve the desired RPM.
OBDII Code P1504 Ford - Intake Air Control Circuit Malfunction - AutoCodes.com
P1504 Ford Code - Intake Air Control Circuit Malfunction
What does this mean?

What are the Possible Causes of the DTC P1504 Ford?

  • Faulty Idle Air Control Valve
  • Idle Air Control Valve harness is open or shorted
  • Idle Air Control Valve circuit poor electrical connection
  • Faulty Powertrain Control Module (PCM)

How to Fix the DTC P1504 Ford?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1504 Ford code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P1504 Ford code?

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Need Help with the Code?

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Information for Specific Ford Models

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P1504 Ford Code

No Frequently Asked Questions about P1504 Ford Code found.

Discuss the causes and fixes for P1504 Ford OBDII Code

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  • Have a po302. Po122 and a p1504 code showing on my ford windstar 3.8. What do I change 1st. Already changed the spark plug on cylinder 2. Does not run any better

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  • P0122 it's probably not related to the problem. P1504 may be caused by the cylinder misfired. I recommend to try to fix the P0302 code first. Check for intake leak around cylinder #2 or possible bad fuel injector.

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  • Have a 02 gt mustang with 4.6. Code p1504 shows up and since I drove home on 7 cylinders due to one blowing out of head I have since tapped and put new plugs and accel coil packs but has been idling at 2300 rpm and will not drop. I changed icmv with a Napa part and tps but no change so put back on original.no vacuum leaks or misfire. Stumped on this one! Checked voltage to tps at key on and throttle wide open and within specs...any suggestions? Thanks

    Reply to Comment

  • Can you tell me if a "faulty" Idle air control valve can be working intermittently or is it a hard fail?

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  • Yes, it is possible for the valve to work intermittently

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  • I have 2002 Mercury Mountaineer With 3 codes p1504 p0113 P0122 but rpm is actual problem is to hight When I push the brakes do not lower the rpm

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  • My question is for what code I can start

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  • These problems appeared after i buy the new engine

    Reply to Comment

  • Clear all the codes and start with the code that comes back first.

    Reply to Comment
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